I can absolutely relate to the staggering confusion that stems from sexual abuse at such a young age. That confusion is amplified by a young female perpetrator that much more because society doesn't seem young girls as capable of such behavior. My perpetrator wouldn't have aroused any suspicions walking down the street as an 8 year old girl, that's for sure. Society has this idea that the people to fear all display signs that they're capable of such behavior, and you just have to channel surf for a minute to see it...people suspect men in hoodies in dark allies to do this. A young girl as a sexual abuser breaks society's mold of what an abuser looks like. Which is something we need to get through to people. Perpetrators can surprise you. They are nearly always someone the survivor knows. (I say survivor because victim doesn't even come close to explaining the strength and fortitude it takes to survive sexual assault/abuse/rape.)
In my opinion, despite your perpetrator being your cousin, what she did to you was indeed abuse. But almost undoubtedly the behavior was learned, and I believe her testimony about her abuse. There's way too much on the line for anyone to make up a story like that, which is something society needs to get their head around, that survivors stories are REAL.
That said, despite it being abuse, you can have compassion for what she went through. That is completely understandable, I worry that my perpetrator was serially abused, I just don't know by who. And you seem to have tried to have reached out to your cousin, and the fact that the family has rallied against her and around your uncle is a true tragedy. As tough as it is though, I think you need to focus on your healing. If the opportunity arises and you get back in touch with her and can help, definitely try, but be sure not to lose yourself in the process. Best to have two feet steady on the ground before undertaking something that big, in my opinion.
Confusion is part of the process, so don't be too hard on yourself. Believe me, I'm in the same stage, so its something I'm trying to hold myself to as well. Once you get through the confusion though you can start becoming aware of the specific emotions and sensations that come up around events in your life. And that's where the real progress begins.
I hope this helps. PM if you want too.