no... it doesn't mean anything
girl: "So, what kinda girls are you into?"
this is a females way to find out if you're either weird (discovering your fetishes) or to know your desperation... it could mean anything, but it doesn't get you to first base.
She could be looking out for one of her single friends, that she could fix you up with depending on what you say. But with this girl, you're not gonna get her. She told you she has a boyfriend... right? Did you ASK her if she had a boyfriend, or did she TELL you? If you asked, that wasn't smart (but in a way it is), and if she just TOLD you, that's her way of saying "so back the hell up, can't have these goodies.."
So, stop letting this question in your mind develop into something it's not, it honestly wasn't worth posting on this forum. You know it didn't mean anything, it's only a question. If you let this question develop into something unreal in your mind, you're gonna get "one-itis". Ain't that a bytch?