Friend in early middle school

I was in 6th grade, i had invited my friend i knew since 1st grade to my house and my cousins were there too. My friend had a lot of issues and was kind of hypersexual i guess, she had been getting much more possessive as well. I was sitting in the corner drawing on my laptop and she asked me really loudly if i was looking at photos of boys for some reason. I was really confused and turned the screen to show her i had been drawing. At some point I got up and she groped me. I turned around and asked her why she did that and she denied it, she was the only one near me who was in reach but she blamed it on my cousin. I didnt understand why I was so upset by it, later my mom called me upstairs because she was annoyed that my friend was making so much noise (loudly shouting and cursing), as my grandfather was sick and trying to rest. I started crying and told my mom what my friend had done, I was very confused why I was upset by it. My mom was very shocked because she trusted the friend a lot, she was allowed to come into my house whenever she liked. My mom told me if I wanted to send her home early I could, but I didnt want to because I felt bad and like it wasn't a big deal. For a lot longer she continued acting like this, touching, showing me weird photos, making weird remarks, but i still wanted to be friends with her. One time we swam in the pool at my house, afterwards we had to shower. I wasnt sure about it, she convinced me, I couldnt come up with some logical reason as to why I shouldnt have. I did. She insisted I should take off my swimsuit, and that its fine because we're both girls. I did but I kept my bra and underwear on. She insisted on washing me herself, I let her. Later my mom heard two voices coming out of the shower at once and came in and saw what was happening. We convinced her it wasnt anything bad, just two children not understanding whats inappropriate and what isnt, she wasnt entirely convinced but let it slide. She continued making me do stuff like this, she'd destroy my stuff and hurt me too. We were both really messed up. Its pretty much water under the bridge now, we're very close now and shes gotten over most of her problems, she dosnt treat me badly anymore and we dont bring it up. I dont have a grudge against her but i feel stupid. I still cant tell when people are being malicious, something similar to this happened to me with an adult as well and for longer than it did with her, I still couldn't tell. Overall im doing much better now though, all of middle school was really rough for me mentally as well as the first year of highschool. Almost all effects of any SA ive experienced (from this friend and other sources) have been improved upon, Im much happier now