Exactly, mudcrutch. While I am 34 and don’t get carded nearly as much as I did 5 years ago (and was also carded to buy a lousy lottery ticket – wouldn’t have been so bad if I’d won, but…no), I am often told that I look about 25. I don’t mind at all, and am thinking of the money I’ll save by not undergoing Plastic Surgery when I’m 50, and everyone else has gone under the knife!
It’s no fun, is it? Especially job interviews…you probably know the look when you introduce yourself that says " This person can’t have done what they claim on their resume’, they’re too young."
I’m going to be 27 in April, and apparently I look around 20, since people more often guess I’m my brother’s twin than my own age. (actually, people guess I’m a teen more often than my age too, but…) Short doesn’t help, it just makes people more inclined to guess you’re young and still growing.
mudcrutch, good luck with your quest to find something good about it… hey, at least we can go to kids movies without kids and not get strange looks 
I’m going on 27 and I get carded for everything! R-rated movies, lighters, beer, cigs… you name it, I also get accused of having a fake id quite frequently. Sometimes its nice to look so young, but for the most part it annoys me because no-one takes me seriously (ie. I must be young, therefore have no clue).
The older people get, the younger they think others are. I’m 30, and most people around my age guess me at 26-28… but ask an old person… heck, they think I’m 17. Looking 15 at age 20 is not that uncommon, you still need to get a little weathered from life. Facial hair and lifting weights might help you if you are attempting to look your true “ripe” age of 20
I’m 32 and am still often carded at the grocery store if I buy wine. I usually don’t get carded at a restaurant or liquor store, though.
I find it to be not at all flattering; I don’t think I look that young, it is just that I am petite and so that must mean I am a child. Everyone says it will be great when I am 40, but they said that, too, about 30. If you find it annoying now, you will find it annoying always.
Preach it, Cardinal! At work, I dress conservatively, act professionally, and don’t discuss my personal life. This rarely stops folks from assuming I’m the intern. The fact that I have an advanced degree and years of experience in the field apparently doesn’t outweigh the fact that I look 18. And believe me, it’s not a compliment to be told, “You’re so well-spoken for someone your age.”
I do carry my birth certificate around with me for this very reason. I’ll be 24 in April, and I still get carded for cigarettes and alcohol. It’s not that annoying anymore, since I’m used to it now.
-Dirty
All things being equal, receding hair and a fat middle make a person look older in a not very attractive way. Clothing, hair, facial hair also can affect how you look agewise - beard, conservative hair, sportsjacket = older. goatee, spikey or shaved head, A&F clothes = younger.
Other things like having a proportionately large head (which you can’t do anything about) may also make you appear younger.
I didn’t say any of this was written in stone. But generally speaking, wrinkleface is not attractive, especially on women. Men also generally age better than women (show me the female equivalent of Sean Connery), probably because much of our attractiveness is not tied to simply looking pretty.
People who don’t like to be hassled. But now that I think about it, if I’m 85 and hittin 23 year olds, WTF do I care if chumps think about how appropriate it is?
Actually, I haven’t had that particular problem yet, because I’ve been in school (except for the past year) and haven’t had to work. Also, I’ve usually gotten the “oh my GOD she’s disabled!” look instead of the “she’s too young!” look when I’ve tried, and since I couldn’t handle school and work at the same time I haven’t tried as hard as I might have if I HAD HAD HAD to work. (No wheelchair, though I’m considering a scooter for long distances; I have a weird orthopedic problem that, among other things, makes me have BAD scoliosis. Impressively bad. Oh, my poor back!)
It’s going to be interesting once I do finish school, because I want to teach early grades – preferably not older than third. I know I’ll have to some fast talking to convince people that I can keep a group of kids in hand. Kids are FASCINATED with me, so I don’t think that’ll be as much a problem as some might think.
I will be 42 this September. I look like I’m 22. Advantages of looking young? I don’t need plastic surgery yet, unlike most of my sun-worshipping, same-age pals (some of whom who’ve already gone under the knife).
Saves money, baby.