How often should I text the girl I like?

So I have liked this girl for three year, and he know that I have liked her for that time too. She has never told anyone, to my knowledge, that she likes someone. So during the end of school I was able to snag her number. And since then I have texted her a few times. I try not be overbearing so I text her once a week or less. She always responds to my texts pretty quickly, but when she responds she will usually just have some quick little text, and will sometimes ask me questions back. So am I doing everything right? Is there any hint that she likes me or wants to get rid of me? Any hints from anyone? Girls would be prefered. Also I don't think she is mean enough to tell me that she doesn't want to talk to me anymore which makes this pretty important.