In love with a lesbian girl

I'm in love with a girl who's 100% lesbian, but I can't get her out of my head. It's a really complicated situation, and I don't know what to do. When I try to flirt with her, she doesn't seem interested, but sometimes she's the one who acts like we're together. And I'm afraid she'll get into a relationship because I know I'll be jealous. I came here to talk about it and see if anyone has any advice; I don't really have anyone to talk to about it. I hope I get some answers. Thanks.