Kinda a weird situation.. What am I to do next?

You really should be honest with her and tell her that you are interested. Because, how does she know otherwise? It sounds like she might be interested, but remember she has a BF. I can tell you from experience that if a girl has a BF, she wouldn't flirt or put herself out there if she was 100% happy. Be honest with her. And if it doesn't work out... well don't wait! There are many fish in the sea!