I'm 14 and plan on keeping mine for a looong time.
I want to try to wait till I'm married, but I think I would be comfortable when I am at least 18 and have been going out with a guy for at least a year and feel that we are truely in love and would not desert one another.
Selfconciousness helps with abstinence I think, thats part of why I want to wait. I really do not like my appearance with no clothes on, and I would be scared that any guy I would have sex with, at any age, would see me and then not want to do it anymore. And also, it's not like I'm beating off guys with sticks anyways. Check out the "when was your first real kiss?" thread...I haven't had one.
But that's besides the point. Let's say theoretically I had the chance to have sex and I was comfortable with myself, I think I'm too young and wouldn't do it. One of my friends lost her virginity when she was 13 (and drunk..but lets not go into that) and she says she regrets it, and I don't want to be like her.