A girl wants to be my friend but i dont want 2 be hers?

theres this girl who was new at our skool last year.Lets call her jenny.she used to act like she was better than evryone else and she also acted hard to get. she was really rude and she thought she was so cool. ppl tried hanging out with her but she was too self obsessed so evry 1 ended up hating her, including me, and she became a loner by the end of last year. this year ppl still hate her. so at the begining of this year i saw her sittin alone at lunch and felt bad for her so i sat with her, she was actually nice. but then she started getting too close to me and started talking **** about my best frnd. and now shes tryin to seperate me from all of my frnds and shes too clingy and annoying. and shes starting to act rude again and she told one of my frnds that she hates her right to her face, and it wasnt a joke. one of my frnds, who is a jock btw, almost hit me with a basket ball but it was an accident so jenny went and beat him up. shes way too clingy and i dont wana even talk to her any advice?