18. This year in fact.
I did it with my girlfriend of almost 1 straight year but we've been out before when I was 16... Basically, her ex used to force himself on her all the time when she was 14 (eww) and his friend tried to rape her. So she was so scared, and I liked her too much to push for anything.
We had put it off and off because we were enjoying whatever we were doing... Our friends had built up all this pressure so we became worried about it...But we eventually came to our senses...
Either way, i wish i'd done it sooner, but I enjoy it too much to care about crap like that. To put it nicely, its good stuff.
We can't believe we got all worried about it, it's great.