Has my window closed?

So last month I talked to an extremely pretty girl in one of my classes who I am sure had a crush on me for most of the semester because she always looked at me and smiled. When I finally talked to her she offered me her number and complimented me on my clothes so I thought she was pretty interested.

I asked her to hang out once but she had to go back home as classes were ending that next day.

We texted a few times and she seemed really enthusiastic but then she would never reply (or take a while to text back). I went home for break and didn't really talk to her (I did send her a text on Christmas which she enthusiastically responded to) and now since I've been back at school when I see her or walk by she takes her phone out pretends to look at it or just ignores me.

What should I do? I can't stop thinking about what I may have done to her and it's killing me! Has my window closed? I was going to ask her out on Valentine's Day but if she doesn't like me then I'll just move on.

Stop with the texting and go up to her and chat her up. Show her that you desire her, flatter her with a cocky comment, a little teasing....man up bro.