A little girl help please, i need your opinion.?

Okay so to sum it up, I met this girl a few months ago and work and she came on to me all flirty and I could obviously tell she liked me. Till this day she is still texing me like crazy asking what im doing and all that good stuff. Occasionally she likes to tease me by sending texts like "i just took a shower, what are you doing". This girl seems perfect to me but there is an issue that I cant work around.....Everytime I ask her to hang out she says she is busy. I have offered to do something with a group of my friends or go to a football game with her but till she says she is too busy...I know for a fact that she likes me still but I cant figure her out. I think something happened to her in the past to where she is very spectacle to who she is around. How long should I keep playing games with her and what can I try to make her feel as comfortable as possible?