That’s similar to me and one of my best friends. I was best friends with this older boy, I was in 7th grade and he was in 9th grade so I was totally in love with him. She was my age and about the time we were in 9th grade, she started to like him and would hang out with us to get on my good side because I was protective of him. Eventually, I get over my crush, they actually start dating and we were best friends for a while.
Then he made some bad life choices and we stuck together without him. We got to talking and I always thought she was a stuck up bitch plus she has this horrible mother. She thought I was basically a street urchin. We bonded, I un-sheltered her and taught her about life outside her horrible mother’s house and we’re best friends today all because we hated each other and liked the same boy. I met my current wonderful boyfriend through her, and she finally learned adequate sex ed from me and lost her virginity to someone I introduced her too. I baked her a cake.