She's gotta be into me at least a little bit right?

So this girl has to like me or at least be a little into me. She has a bf but we flirt and hang out and stuff but anyways there's this new girl I have a little bit of a crush on and the other girl got into a bad mood like immediately after me and the new girl were flirting in front of her and now doesn't wanna go bowling after I invited her to go bowling with us and a couple other people. Like wtf? What kind of girl gets mad if someone who's not your bf is flirting with someone if you're not into him? Especially when you have a bf.