Bi? FWB?

So I really want to have sex with one of my girl friends. I'm not sure why but I just want to so bad. I have a boyfriend and we talked about what would happen if I ever hooked up with a girl and it doesn't bother him even if he's not there (as long as there's no guy involved) anyways she's bi and I asked her if she's into me and she said "girl you know I think you're hot af" and then I said "so is that a small yes?" And she just put "yeah girl" no emojis or anything. It just seems so blown over and as if she didn't want to hurt my feelings. Idk am I over thinking it? What should I do? I just feel like I'm putting a lot of thought and stalk into this and she honestly isn't interested/cares