Girl Problem

So I’ve been best friends with this girl since 4th or 5th grade (let’s call her E). I’m in 7th grade now. Even though we haven’t been best friends for very long, I would have easily died for her (I’m rlly trusting). Well when we started getting close my other bestie (let’s call her M) warned me about her. She said E was only looking for attention and would backstab me. Well I made one of the worst decisions of my life and decided to choose E over M. Even though M and I had been bffs since 1st grade. Even though E was definitely not the best person. At that time, E was a lot nicer than she is now. But she progressively got worse. She started talking about people behind their back more and more. She constantly asked me to do her homework bc she didn’t want to do it (I’m in advanced classes for math, english, science, and history). I didn’t care bc I figured that we were best friends and she would never use or hurt me. Then 7th grade came. At first we were fine but that lasted not even a month. By September she was hanging out with the more popular kids in our grade and basically ignoring me. She starting talking shit about one of my closest friends to me and everyone that would listen but I still let it continue. I know I’m a horrible person for letting this go on and I rlly regret it especially bc it took so long to figure out she didn’t think of me as a best friend. How did I figure out this? It was actually a pretty slow process at first until it gained momentum. The event that started everything was a football game. I would have to remind myself to not cry and have a breakdown almost every minute. It was torture. I told E about it and how I thought I had anxiety and at first she was rlly supportive but then she started ignoring me again. I was devastated but I finally realized what kind of person she was. E made me so unhappy and basically only needed me now for good grades. I started to realize I had depression and I leaned a lot on my real friends. I got so much closer with M and started liking this one kid (he’s my first crush and yes ik it’s pretty late to have a first crush but whatever). I hate confrontation though so I still pretended to be friends with E. Well I went through a really bad week 2 weeks ago and I wanted to hurt myself. One of my new best friends (we’ll call her A) also suffers from depression and other mental illnesses bc of her past and mainly helped me get through that week. During that week, I realized that I was doing to E exactly what she had done to me. So I decided we needed to talk. Oh yeah, she also told my crush I liked him and apparently some other stuff. We’re like polar opposites tho so I don’t think he believed her. I texted E and asked to talk. I waited a day for her to respond. She didn’t so I essentially told her if this was how she was going to treat me then we’re not friends anymore. I felt rlly good about myself and but I also knew she would talk shit about me for awhile. Then one of my friends says E got her phone taken away and couldn’t text me back. Me being the naive person I am decided to tell E that I WAS THE ONE THAT SHOULD BE SORRY and I wanted to be friends again. Well we’re friends now and I don’t like it but I’m too nice to tell her goodbye. And I’m rlly sorry bc this is rlly long but I do have pretty good news! I told my crush I liked him and asked if he liked me back and he said yes! The next day he asked me to be his girlfriend so of course I said yes! We texted for an hour and a half last night and he makes me so much happier. Unfortunately, I’m not allowed to date so my parents don’t know why I’m always so happy now but it’s alright. Anyway can you pls just give me advice on what to do? Ik this was basically a rant but I’m just kinda done with E.