Well according to my Sunday school (Franciscan bros et al), she was 15-16 and Joe was perceived as an average looking prematurely gray haired guy in his early forties. They were both, like, super old, when you are eight or nine.
Mostly right, though since this is GQ we should be a little careful. There is tendency I’ve noted for folks to argue that once you survived childhood, pre-modern lifespans were similar to modern ones. They were not.
Pre-modern people who did survive childhood did not usually make it to 70 or beyond. They could, but it was pretty rare. The average lifespan in ancient Egypt was an appalling 19 partially due to the high child mortality you mention AND the average adult lifespan based on analysis of skeletal remains was in the mid-30’s due to chronic malnutrition and a( very short )lifetime of truly backbreaking labor. The poor peasantry that were dieing in their 30’s also probably did so in a great deal pain much of the time with teeth already worn down to the dentine and fucked up joints. You were lucky to make it to 35 back then. Ancient Greece wasn’t much better.
Similarly, just not as bad in the Middle Ages. If we discount the brief reign( as consort )of Philip I of Spain who made it to the stunning age of 71 in 1598, not a single English/British monarch made to 70 until George V who died in 1936. The ones who went of old age mostly went in their 50’s. Pretty much the same in France - Louis XIV was the first to beat the 70 barrier. Usually nobody got that close to it.
“ not a single English/British monarch made to 70 until George V who died in 1936”
Victoria lived to 81.
Another, equally valid way to resolve this is to say that some storyteller made it up. We know that many biblical stories were made up, even “forged” to fill narrative gaps, and consistency be damned.
Would you believe 39? In this era? That’s how old my Mom was when she had me. Although I do like to think of her as unusual in some ways. 
Mary is traditionally depicted as rather young, but not a child – say about 20.
Joseph could have been any age, and I’ve seen depictions of him being mis-20s to an old man.
The “old man” hypothesis seems to have come about as a result of trying to keep the written sources and dogmatic theology in line. Scripture clearly says that Jesus had brothers and sisters (as noted above). Some tried to weasel out of the obvious meaning by claiming that this actually referred to cousins, or some other relatives. But another way to square it was to imagine that Joseph had had already married, and had children by that marriage, and that these half-brothers and half-sisters were the ones referred to. Then the older Joseph married the young virginal Mary, and she conceived Jesus, but, apparently, they never had sex, and so she got to stay a virgin.
I think some of this is in Apocryphal books that didn’t make the cut to stay in the Bible, but managed to survive, nonetheless, while the rest is speculation by priests and artists in the Middle Ages and beyond. Certainly you can find paintings from the 16th century onward depicting an elderly Joseph. In fact, some go a bit comic, showing the old Joseph – who must have thought himself past this sort of thing – drying baby diapers.
Of course, if you don’t buy the Apocrypha and don’t feel compelled to insist that Mary didn’t remain a perpetual virgin, the need for all this framework of speculation collapses, and you could have a Joseph of any age. In his movie The Gospel According to St. Matthew, Pier Paolo Pasolini had a circa 20year-old Mary and a Joseph of about 30. It’s interesting that, when Jesus was on his way to the cross on the Via Dolorosa, Pasolini had his own mother play Mary, and she looks a lot older than the 53 years she should be.
Ah, got me - I missed Victoria some how. Okay, 1901 then :).
1889, then. 
George III `the King who lost America’ was almost 82 when he died. His predecessor and grandfather George II died shortly before his 77th birthday.
Edgar Ætheling was nominally King of England after King Harold lost his life at the Batlte of Hastings (possibly by the hand of Duke William himself). He died at about age 75.
King William IV was almost 72 when he died.
Robert de Brus was a candidate for King of Scots but died about age 80 before he could be crowned. Malcolm II King of Scots also died at about age 80. Three other Kings of Scots died in their 70’s.
William IV 71
George III 81
George II 76
Honoury mention (not rulers at age of death)
Edgar Ætheling 75
Richard Cromwell 85
and Elizabeth I who was only a couple of months shy of 70.
Partially ninjaed by Septimus
I haven’t seen this movie and don’t know what this woman looked like, but life would have made a person of 53 look much, much older.
Even nowadays, I’ve read about Western reporters who went to places like Myanmar or Somalia and marveled at all the “old” men and women, until they found out that these people were probably in their 40s or 50s.
The other way to resolve this: Mary did NOT remain a virgin, and she and Joseph had other kids. There’s nothing theologically faulty in believing this because Biblically, nothing indicates anything about Mary remaining virginal after the birth of Jesus.
I mean, some doctrines believe a woman named Veronica wiped Jesus’ head with her veil while he was carrying his cross. But Biblically, there’s no reason to believe this either.
I mean, sure you can believe stuff outside of the four Gospels about Jesus’ life, or you can *not *believe the stuff *inside *of the four Gospels about Jesus’ life, but if we’re just answering questions based on canon for GQ purposes, there was no Veronica, there’s no reason to believe Mary remained a virgin, and there’s no way to know how old Mary was when she conceived Jesus.
I refuse to accept Edgar! Or Cromwell! 
Mea culpas for my sloppy research ;). Still, my basic point stands. It’s not just better childhood survival rates pushing life expectancy in recent centuries. It’s better nutrition and health care as well.
George III lived to 81
William IV till 71
Catholic dogma is a lot of the reason for the tradition, but far from the only reason.
Consider–
#1, We know that–in general–women outlive men. But,
#2, Joseph is never once mentioned in the present tense once Jesus becomes an adult.
#3, As Jesus was hanging on the Cross, he commended Mary into the care of the Apostle John. If Joseph were still alive, such a move would have been unnecessary.
Conclusion–
It is quite likely that Joseph was significantly older than Mary.
According to the Gospel of Luke, John the Baptist was born to his mother, Elizabeth, when she was quite old (e.g., near menopause).
During Elizabeth’s pregnancy, Mary traveled to Hebron, and helped to care for her for the final three months of the pregnancy. Once John the Baptist was born, Mary returned to “her own house”. I couldn’t say whether “her own house” would mean her parents house or, literally, her own house. It’s strange that Luke wouldn’t mention Mary’s parents as he was trying to collect as many extra details like that as he could, and Acts (also by him) makes it clear that Mary was still alive and in Jerusalem with the Jewish church soon after her son’s death. Her parentage is information that we would expect him to be able to get, and yet he doesn’t. That could imply that she was on her own for some reason - lived as an orphan, etc. - to that she was disowned by her family, at some point in time; or it could just mean that Luke had only so much parchment to write on and some tidbits didn’t make the cut for inclusion. It’s hard to make any guess.
But, we are told that she traveled 80 miles - seemingly by herself - just after becoming betrothed to Joseph and having God tell her that she was going to become his…well, baby-mama for lack of a better word. It’s likely that she would have been on foot, so we can estimate ~15 miles travel per day, so that’s a 4-6 day trip.
During medieval times, as far as I can tell, most women who traveled any great distance either did so with her father or husband, or were widowers. And, even in modern day, in most countries of Asia and the Middle East (that I know of), women are expected to either live with their parents or their husband, and any young single girl is viewed as though she would be kidnapped, raped, and turned into a slave should she ever leave sight of a male overseer that the family trusts. Not for daily life - going to the shop and whatever - but when it comes to questions like going to a party or going to visit another family, and certainly for long-distance travel.
On the other hand, for rank peasants, that standard could be different. It could be normal for young peasant girls and boys to be traveling all over the place, in those times, and they were just invisible to the sorts of people who would be writing stuff down. But I feel like, even in modern day, a 14 year old teen girl in the middle of nowhere India isn’t going to be walking by herself for 5 days, unless there’s more to the story.
If Mary was acting as a midwife and traveling around by herself for pretty good distances, I would expect her to be older - 30, 35, 40, etc. - if not a widower. She would need to be the sort of spinstress that you could see it taking a while and a bit of effort to arrange a husband for. And it would make sense that she would go to see her fellow cousin, if they were closer to each other in age and had that sort of personal connection of having grown up together. (Granted, it could be her mom and her cousin with that relation - but then why doesn’t mom go?)
But you could also make arguments that she could be some wild girl who left home at a young age, figured out how to make a living on the streets, and somehow was independent, or that she was living in a very trusting impoverished family who simply didn’t have the status to care about their daughter’s virtue compared to trying to help their cousin.
Of all of the options, I would probably go with the spinstress as the most likely, if we trust the canonical information that she was going back to “her house” from Hebron, and not to like “the house of ladies of ill-repute”.
Though, if we don’t entirely trust the canonical sources, then I would note that it’s highly unlikely that Mary was actually cousins with John the Baptist’s mother. Nazareth, at the time of Jesus’ life, was a shanty town built for itinerant laborers to help rebuild the city of Sepphoris. That’s not where the cousin of a priest of the Temple in Jerusalem comes from in ancient/traditional classist societies. We would also expect to see a whole slew of mentions of the relationship between John and Jesus throughout the Bible and particularly in the Gnostic apocrypha, if there was one. But instead when, for example, Peter and his cousins join Jesus’ church after John’s death, there’s no mention that Jesus was related to the guy and so it makes some sense for him to take over John’s following. As far as the text describes, Jesus is just another guy teaching similar things as John was, and we see other people also taking over John’s followers after his death - Simon Magus and Dositheos - so any kinship claim would have been a strong argument for the early church that those followers should have come to Jesus, not to those other guys, but there is no such argument made.
We should also note that Jesus’ two separate and irreconcilable paternal pathways back to David are almost certainly false; the story of the census, the murder of all of the babies, the birth in Bethlehem, etc. are all considered to be false by most Biblical scholars; and that nearly all of the information which we have about Jesus is really just about the brief period between when John died and when Jesus died, which doesn’t make a lot of sense given that the Jerusalem church was packed full of Jesus’ family - Mary, James the Just, Clopas, etc. - and continued to be lead by them up until at least the destruction of Jerusalem in 70 AD, with Simeon the son of Clopas being proclaimed the new Bishop of Jerusalem by the Orhodox church. They had access to people in Jesus’ family, who could have told them about Jesus’ life and teachings before John the Baptist, and yet based on what we can see we only seem to have information from the people who are post-John or that the family was only willing to tell people about Jesus’ life after John.
Overall, I would say that this is an area where it’s probably bad to even make simple assumptions like, “Well, most girls have their first kid (during that era) at 15, so that’s probably when.” When it comes to everything before John the Baptist’s death, the Bible is a regularly dishonest work and jumps right over 30 years of the man’s life, from his birth to the last few months that he was alive. There are areas of the Gospels that you can read and you’re probably getting some factual information from history. But when it comes to the early-days, making an assumption of normalcy is belied by their aggressive aim to avoid discussing it and the complete rewrites of the history. Where it may be that, with most women, you could safely assume that she was a teen, with Mary, you really can’t rule out everything from her being a spinstress, to a widower, to a prostitute, to a regular peasant girl, to a traveling witch that hocked snake oil.
Minus evidence, it’s reasonable to propose something normal. Given the inconsistencies and lies, I think it’s unreasonable to even do that much.
Factually: We don’t know
IMHO: We shouldn’t even guess.
Remember that famous National Geographic photograph of the Afghan girl with the striking green eyes? She was 12 years old at the time, although to Western eyes, based just on that one photograph, she could have been mistaken for a woman in her twenties.
The photographer sought her out again when she was around 30. The years had not been kind to her.
Sage Rat, why wouldn’t you assume that “her own house” was the house where she was living with Joseph? She was betrothed to him, and pregnant with a baby whose parentage he was not disputing-- Wouldn’t they be expected to be living together?
So far as I can tell, even in the time and place of which we are speaking, wedding ceremonies were practiced and usually a wedding requires at least that the two people getting married are alive and present. When one of them is 80 miles away and you don’t have video chat over Skype, you sort of have to wait.
If she left betrothed, then I would expect her to return betrothed, but not married. And, from a more practical standpoint, I doubt that most women would want to arrive at their new husband’s house after a five day walk with 30-40 pounds on her back, sweaty and tired.
Now, granted, they could be skipping ahead in the description and we’re supposed to assume that it is meant that she went more-or-less straight to her husband’s house, but I feel like then they would just say that. Adding an extra story about Mary’s parents takes up real parchment space where switching “to her house” for “to her husband’s house” doesn’t in any real way. And, I would tend to think, this is the sort of instance where being clear on how close Mary’s womb was to the penis of a man with whom it would be natural for her to have sexual relations with is sort of integral, so it would be worth adding that extra word if that’s the direction that they wanted to go.
Granted, I don’t speak ancient Greek, so it may just be that they didn’t have or didn’t tend to use such specific language at the time. But everything which I have seen that analyzes the text, seems to be talking about the words in much the same way that we would, with no mention of a “to her husband’s house” as an alternate reading. But I’ll grant that this is not a topic that I’ve dived into deeply.
People didn’t routinely live to 70 in the past. The life expectancy for people who lived to be 20 reached 40 years only during the second part of the 19th century in Europe. Meaning that even if you didn’t die during childhood/adolescence, you would still live only until 60 on average at that time and this was already a progress.
During the renaissance, people who reached adult age only lived to their mid-50s on average. Between 1000 and 1500, no king of France and only one (or two, can’t remember) king of England lived to be 60, as an example. That’s a lot of people who never reached 70, and that’s not atypical. The average age at death (excluding the one short-lived king who died in infancy) was in the late 40s for French kings (despite none of them dying in battle or assassinated during this period), and early 50s for English kings, which would have been pretty normal for the era.
People could, of course, live to 70 or 80 but these were lucky outliers, given how many ways there were to die early : childbirth, diseases and epidemics, infected minor wounds… You wouldn’t survive a serious bone fracture, let alone appendicitis, and then there’s malaria, smallpox and so on. And possibly famine. Ask around you and you might be surprised by how many people you know who would have been already dead without modern medicine, and that’s despite the fact that we don’t have major epidemics anymore, a lot of vaccines and are well-fed.
Our perception is skewed because a significant number of famous people lived long. But that’s not a representative sample. You don’t become a famous general, politician or writer if you’re dead by the age of 30. In fact, that’s also true for kings. Pretty much all the famous kings had an unusually long reign, and pretty much all the kings who had an unusually long reign are famous. The regular king who died at 35 from dysentery after 6 years of reign isn’t present in people’s mind, so they have a skewed perception of the actual age of death in those times.
Relevant to this thread, it’s not impossible, but still not very likely, that Mary or Joseph would have lived until 70.
So God likes 'em young?