[hocus pocus]

The sex of someone doesn't matter when it comes to sexual assault. Assault does not discriminate.

It all depends on how old N was. If N was significantly older than you, old enough to know about sex, but under the age of eighteen, then this was child-on-child sexual abuse. Normally, this type of abuse is when older children who are aware of what they are doing abuse younger children. But child-on-child sexual abuse doesn't have a lot of information out there that I am aware of and the lines could be blurry if that makes sense. If she was an adult, it was abuse as well.

If N was the same age or younger, I highly doubt she knew what she was doing. Children do experiment, but they generally don't force other children into things and they don't know a lot of things about sex. If they do, that indicates that someone has likely abused them. Sometimes, abusers will force children to do sexual things to each other for their own pleasure and that could have happened to N. It sounds to me like N was abused and wasn't aware that the behavior was wrong, and was just doing what she knew but was doing it with you.