She likes me but SHE HAS A BOYFRIEND?

We are both freshman at a community college and she's in one of my classes. She is showing various signs that she is interested in me, however I just added her as a friend on instagrahm, and it is evident that she has a boyfriend. (The last pic of him was posted 4 days ago) I also noticed that she deleted 4 pictures before accepting my friend request. Why would she flirt with me and waste both of our time, if she has a boyfriend? I am thinking about asking her out anyway.
She likes me but SHE HAS A BOYFRIEND?
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