Why hasnt she txt back? (girls) 10 pts!!!?

So this girl I met off facebook gave me her number on last thursday so I thought id gie it a few days before I txt her back. So Sunday night I txted her but hey, its bobby around 930pm. She never txted back. How long will a girl take to txt back? Or what should I do? Read my other posts to get full story. 10 pts to.best answer, I promise!!