How do I tell her to stop. She doesn't listen?

So, I'm 16 and my bi sexual friend came out to me 3 weeks ago. I had no problem with her being bi. She told me she liked me, so I told her I'm straight and didn't like her, but now she's like being weird. She'll text me little <3 and she'll tell me she loves me. Then on facebook she tagged me in a post telling me she loved me. Now everybody thinks I'm a lesbian. Just last night she sent me a relationship thing on facebook and when I rejected it, SHE CAME TO MY HOUSE AND KNOCKED ON MY EFFING WINDOW AND TOLD ME THAT WE WERE GOING TO SEE A MOVIE. Just tonight she keeps sending me messages on facebook about how she loves me and wants to have s3x. Her first message literally said "I want our 1st time to b special <33" She thinks where in a relationship or something. I want to be her friend, but I don't want to be her girlfriend. How can I tell her this?? Thanks xoxo