About 17. I was freaked out by classmates starting when only 14. They would write suggestive BS on the blackboard before the teacher got into class. I was just like WTF??
I didn't ask and they didn't tell. It wasn't until I started working and my best friend who's parents owned the restaurant I worked in that I said OK. It was outdoors on his parents porch. First time didn't get me off. The second time though did the trick. The rest is history.