I'm 22 and still haven't lost it, and its mostly due to choice. I sometimes consider myself old-fashioned based on the few morals that I was raised with and stuck by. And because of that, I've never fully been able to adapt to the popular living ideals of today, because I always feel like I'm doing something to fit in with the crowd.
But I certainly remember some of the pressure that came with it in high school. During the last few weeks of my senior year, my friends tried to pay some girl to kiss me, and she said she'd have sex with me for free. I declined and ended up being called gay just because I didn't want to kiss a girl that spent most of her time doing drugs and drinking during school hours with lots of other guys. It was even worse since it was two of my friends pressuring to do so, when they had yet to have girlfriends themselves.