AITA for being selfish?

I 18f live in a small town. I met a girl in one of our classes. Her name was Melody and she was 18f. That year I struggled quite a bit, but Mel helped me through. That started our friendship. We would spend almost every day together. When school began, I got my license and I already had a car. Mel didn't have a car but she had her license so during the summer, she would drive us everywhere, and in return, I would pay for gas, so it was fair. After I started driving it was me driving everywhere and I was fine with that. We started to hang out more, I was paying for the gas, and a bunch of other things I didn't think were fair for me considering what I had to do during the summer but in fear of losing Mel and being the people pleaser I am, I didn't say anything. Mel found out she was moving from our town but luckily she was only moving 20min away. I told her that we both could take turns driving to each other. it was just me driving every week to her house, and we would go shopping. I was getting annoyed because she finally got her car and had the time to drive it to my house but she always made excuses, I didn't say anything to her and left. A month went by when I noticed that she started talking more to another girl. I didn't care, I was just happy that she had more friends. We started to hang out less. I wouldn't have minded that she brought her other friend when we did but the problem was I was excluded. Mel and the other girl are more skinny than me. When I was hanging out with them, they would take funny pics together of them wearing each other's shoes or clothes, while I was in the background alone. I started to pull away more but I was missing Mel, and I told her how I felt like I was being pushed out and it hurt me to feel that way. Mel said that I wasn't getting pushed out and she's sorry i feel that way and she will change it. Nothing changes, I rarely hang out with Mel and I hear about all this stuff she's doing with other people and I'm not there. But I chalk it to me bring insecure. There are other stories of me being left out and alone. Like her posting all of her friends on her social media, I'm the only one not there. I texted her a letter and said I was tired of being the afterthought and having this one-way friendship, I was the only one reaching out and putting the time to make the friendship. I want that to change, so I gave her the option to work with me to change the friendship or we go on our separate ways. We went back and forth, and she said some shocking and hurtful but there's a lot to add here. Let me know if you want to hear it cause I can make another post. But in the end, she chose separate ways. Am I the asshole?