How do I get my autistic classmate to understand that I don’t wanna be friends with her?

In my history class last year’s school year, there’s this classmate we had and she is on something called autism. I’ve heard something about that but I don’t know about really well. Anyway she seems like a really sweet girl but she’s frankly very annoying. She’s a teachers pet. A kiss ass. Like also, when she gets to answer wrong she does a fit about it every time. It’s very annoying as she kinda gets away with a lot of things just because she’s “special needs”. I mean what’s so special about her needs? Anyways our teacher paired up together which I was not so happy about that. I begged her to let me switch partners but she said her mind was made up. I still think she set me up on purpose. So we were doing a project together and it was like a three week project. I mean I meant to the very great helper I really appreciate. We exchange numbers so we can keep in contact about a project but then afterwards she wouldn’t stop texting me. I told her that we don’t have to text about the project anymore and we’re done. I may I’ll answer her back but she texts me every single day. It’s been like that since May and I’m frankly annoyed. She started texting me a month after our project was done. She keeps telling people that were friends and we’re not. She would say I’m her best friend. I told her that we’re not best friends and can she stop please and stop texting me 15-20 times a day. She said she was sad but she kept doing it and I’m getting very frustrated with her. I would ignore her text messages and I would end up getting 50 text messages from her. I mean she gave up and started texting me back this week after three weeks. Why doesn’t she get it?? Please help!