sexual abuse?

when I was about 6 me and my friend was talking about our private parts and we ended up showing each other and touching, I realised this felt good and from then on I would persuade my other friends to do it also. then one night I slept over my friends house, I was about 12 at this point and she started kissing me and said her uncle taught her how to have sex So she got on top of me and started rubbing herself on me ( I had my first orgasm) and it was something we did regularly .. did I abuse her? did she abuse me? I would ask friends to do it at sleep overs! I thought it was normal and everyone did it.. now I'm 16 and not so sure.