Playing hard to get or just playing games?

M18 – F18 Girl I’ve known for 3 years but just recently in the past 2 months we have started talking seriously.

Meet up a couple times, just little dates and going to each others houses but I’ve noticed she likes to backtalk a lot, every time I try to make the conversation more sexual etc, instead of going with the flow and joining in she kills the vibe and starts to justify what I say, this happens mainly through text but in real life sometimes too.

Is she just using me for non-sexual attention? Or is she playing hard to get? The big ego and throwing me off my game really doesn’t help

Thanks