I kissed a bisexual girl but i'm afraid to do anything else because she's bi?

[Amanda]

I'm 18 and i've never dated a bisexual because all the bi girls i've ever met were fake. I really liked this stud in this support lgbt group I go to. And we would make fun of this bi girl bc she's literally so feminine and she seemed like a b*tch. She tried so hard to fit in with us and she added me on fb, her facebook is a joke she's friends with all these sl*tty girls and there were pictures of her with guys which pissed me off.

I hated her a lot because I thought she was a barsexual tbh. But we had this get together and this girl from our group invited her and that night she was smoking outside and it was just us. She looked really sad and when I asked her what's wrong she told me about how her step dad was sexually abusing her and how when she had a girlfriend last year he beat her up really bad. I felt bad for her and I felt like an idiot for judging her. We talked like all night and I ended up kissing her. I don't know why or if it was just out of pity. But lately i've actually been really attracted to her.. like emotionally

I always thought she was really hot but i'm kind of worried about her being confused/cheating because she's bi. How do I know if she's different?