If the girl is on the top while having sex, does she do anything or does he do the work?

I'm totally confused about my relationship, where it's going, I mean. I'm 14 years old and I have a 16 year old boyfriend, he's turning 17 in a few months. Since he's older, I know he has more sexual feelings and things like that, but I don't think I understand completely. We always fool around...kind of sexually...but not completely. We haven't had sex yet, and I think he might want to. I really don't know if I'm ready, mentally. I think it might ruin the relationship, I don't know what to tell him, or what to do when we start fooling around again. I mean, I enjoy it, but don't know how far to go with it, or where to stop. I feel like I need to talk to him, but no words come out. Whenever we "fool around" he asks like, "Is this okay?" or "Do you want me to stop?" I always let him do whatever, I don't mind at the time. But later on I really regret it, and wish I would have said something. What should I do?