Quote GunstarVixen:
at 25 i sometimes feel old, I just try to cosplay characters that suit my age a little better (she says having just cosplayed a 16 year old, AGAIN!!!)
I cosplayed as a 12-year-old girl earlier this year and (I think) I got away with it. I doubt that's something I'll be able to do much of in the future, mind (if nothing else, I'm not keen on the chest binding

)!
Quote hanagata:
I just turned 27 and Expo London May 2008 was the first time I saw people cosplaying and loved it >_<. So, I'm just starting =/. Some people stop at 21? That makes me feel old(er)

. I really wish I could have done this when I was younger >_<. I've missed so much time :O
It's such an individual thing that I really wouldn't stress about it. Some people just grow out of some things quicker than others, and some never do - that's just life.