Eight years, with both of you being adults, doesn’t seem too bad to me. My husband and I have a 7-year gap (31 and 24 when we met).
This. I think the half your age plus 7 rule is BS.
Oh, and DigitalC also makes an excellent point.
I think it’s fine. But stop saying she is mature for her age, as that’s a classic creep line.
Haven’t read anything but the OP.
I’m also 31, and I’d have no problems dating someone who’s 23. In fact, my preference would be to date someone approximately that age, because I want to have children someday, and the Law of Inverse Fertility and such.
If you’re right for each other, an 8-year age difference isn’t that big of a deal. (Obviously I’d be singing a different tune if you were 20 and she were 12).
I can’t believe anyone here is even batting an eye at it. There’s absolutely nothing weird or creepy at all about a mid-20 year old dating an early-30 year old. How odd that people are making comments like “just squeaking by” and stuff.
My brother has been making puppy eyes for years to a woman who’s got 7 years on him. Apparently, and judging only from the pictures from their last trip and from how much time they’ve been spending together, she has now finally said “well, ok…”
Their mothers have been whispering to each other “hi, co-mother-in-law” “shhh, not so loud, we don’t want to scare her!”
If I said that an 8-year difference, specially one where the guy is older, is something scream-worthy, those two women would toss me into the nearest river! You know how cold the water is right now!
Now seriously: that difference would be a red flag if one of you was in school, or divorced with kids, or… and the other not, but I see no reason why you wouldn’t be a good fit under current circumstances. Best of luck!
My father is ten years older than my mother. They met at college (my dad had gone into the military first to get money for tuition) and married when he was 31 and she was 21. Still married and going strong 53 years later.
That said, I think the “half your age plus seven” rule is a good rule of thumb to go by. It is, as the movie pirates say, not so much a law as a guideline but it helps to give some perspective on what relationships are likely to work vs which ones are likely to have strains placed on them due to the age difference.
As the above cases show there are always exceptions, but exceptions are - tautologically - exceptional. If your relationship falls outside the “half plus seven” range, you’d better have something else going for you outside the norm.
So to sum up: 23 and 31 is fine, as long as you’re not actually *her *teacher.
When we met I was 42 and my wife was 28, we are still married after 32 years, so it can work out.
BTW, my first wife was one year younger than me, my second wife was 10 years younger.
So “half your age plus seven” worked for me.
Congratulations, Quasimodal, on finding someone about which you have such good things to say! Your ages don’t concern me, either, as long as they don’t concern either of you. Best wishes to the both of you! 
Age is only a small part of compatibility. In my first relationship I was 16 years younger, now, I am 5 years and 360 days the elder. I’m very glad I didn’t let my initial reservations about age hold me back.
FWIW - there isn’t a lot of convincing data that marriages with large age gaps result in higher rates of divorce.
As usual - the statistics are complicated by various factors, but if you look at the figure on page six here:
You’ll see - it doesn’t appear to make a huge difference.
This of course assumes you can make it to the getting married part.
I think the “just squeeking by” part is because a 23 she’s not quite a “mid 20-year old”. As WhyNot mentioned, it’s a phase of life thing: a teacher with years of experience dating a college student? There are potentials for problems. A teacher dating another teacher, with the same age gap? Utterly normal. And this girl is on that cusp.
Teen forced marriages between religious fundamentalists don’t tend to break up, either. Doesn’t mean they are good. Divorce is not the only relevant metric.
In general I would discourage young (under 25 or so) people from getting in serious relationships, as a relationship always means giving something up and making choices focused on another person, and at that age relationships are unlikely to last- so you are probably making a real investment and real sacrifices for something that is likely very temporary. This is especially true if you are seriously dating and living together, but don’t have concrete plans for the future. Things like picking your undergrad to be close to your high school boyfriend are often limiting, and ultimately pointlessly so.
And dating someone older often does lead to more commitment faster. People in their 30s and beyond often work on different relationship timescales, as older folks have more relationship experience and self-knowledge
For those interested in very young adults, I think it shows respect to give them time and space to have some independence before rushing in to living together. Have fun, enjoy each other’s company, but encourage them to have space and freedom, and make sure you have a clear and mutually agreed plan for the future before you start acting as a unit.
Congratulations! See? Life can be sweet.
I’m not sure if either of you believe in kids or pets instead, but I hope you name them after authors & live happily ever after. 
I’ll defend the half your age plus seven rule of thumb. But it is just a rule of thumb. Any relationship that violates that rule but is still legal can work (and any time this comes up examples are presented).
For me, the rule of thumb just means that the couple is likely to be at different places and there is a good chance that one will change more than the other as time goes by.
I look at it as an evaluation criteria, not a screening criteria.
Cougar! (translation: You go, girl!)
Right: it’s a guideline, for typical people. (How many “typical people” do you know?) It’s a clue that you might want to give it a second thought, which you’re doing, even though you nearly pass by the rule.
bingo. Just something to think about, along with everything else.
Don’t walk away from the potential for love and happiness because of some silly rule. Also, as mentioned above, early 30’s and early 20’s … common as heck, nothing to raise a ruckus.
In any case, I like the half-plus-7 rule. That means I could date a 35-yr-old. Women in their 30’s are HOT! Just don’t tell my wife, OK?
I’d say 40’s, but no doubt it varies.
People have been saying that for a long time, so I suspect it goes back to Masters & Johnson. I think it was even stated in Ann Landers’s “Everything You Wanted to Know about Sex, But Were Afraid To Ask.”
The title alone reveals how old that book is.
Dude, it’s fine. I turn 40 in April. My wife turns 32 in the beginning of January. We’ve been a thing since I was around 30. So this is pretty much your situation. It has worked out for us just fine.
The big thing you need to be ready for is that you’ve established who you are as an adult, while she’s not going to do that for several years yet. She’s going to change. I can pretty much guarantee you that.
Then there are minor, inconsequential things like your pop culture references not matching up. Movies that you think everyone’s seen, she hasn’t seen, etc. Not a big deal, but kind of a buzzkill when you’re explaining a joke you just made.
When I met my wife, I was 34 and she was 23. We’re still together and doing quite well, 25+ years later.
I didn’t kiss her for the first time until several days after her 24th birthday, but that was just the way it worked out, rather than to stay on the good side of the (age/2)+7 rule, which I’d never heard of anyway at the time.
Yeah, this seems perfectly unobjectionable to me. If she were 18, sure, (then again, my uncle is still married to the woman he met when she was 18 and he 30.) This wouldn’t even register on my radar. Go for it.