I'm not over 25, but still a proud member of the V-team. It's a personal choice I made for myself. First of all, I didn't date during high school and never cared to. Also, I just don't feel like having to deal with the possibility of pregnancy or STDs. I don't want to have to be telling guys they have to get checked before I'm OK w/ moving on. Birth control is really expensive (insurance doesn't cover it if it's for birth control purposes). It hasn't been hard for me and I've never regretted making that choice. One of the dumbest arguements I've heard in favor of having sex for the sake of sex is "well, since you're in a committed relationship, won't you want some experience before you get married?" Um, hello, there are a GAZILLION things you can do besides actual sex between kissing and intercourse! I'm confident with my body and my sexuality and that's enough for right now.
I wouldn't worry too much about it. If you're interested in a relationship, don't focus on looks. If you keept telling yourself you're not good looking enough, then you won't even try to put yourself out there. Confidence and individuality is attractive, low self-esteem is not.