Sexual exploration

I used to sexually experiment with a close friend throughout childhood. We used to play doctor which was pretty innocent at our younger years. But once we got into preteens and early teens we used to imitate sexual acts. Such as oral sex and rubbing our privates against one another simulating sexual intercourse. Never led to any penetration. Never really understood what intercouse was then. I feel really guilty due to the fact I'm 2 years older. I've spoke with her a few times about it. She seems to be very helpful and just chalking it up to being dumb kids. Said don't feel guiltity or no need to worry about it. Sometimes she said I talked her into it cause I was older but said it wasn't a big deal. Why can't I let this go. Should I be able to move on and not stress over it.