I met this Koran chick during tha orientation at my school, and we talked a lot during the first day. I never asked for her #, but the I saw her again and we talked like for a minute and the she asked for my number and we exchanged digits and then I left for class. After that I called her yesterday to ask her if she wanted to grab dinner, she sent me a text sayin she already had had dinner but that next week she was available, the she asked what day was i free. I just told her that she should just call whenever and she told me the same...what should i do should i call her to grab lunch or what step should i follow??? should i start hitting on her right way now that we have talked a lot

First and foremost, slow down. Stop worrying. Take a deep breath and relax. Then call her and talk to her about something completely unrelated to going out. Tell her something you learned in class that you want to share with EVERYONE. Then say you're going out for lunch, and as an afterthought invite her along. If she says no again, wait a couple of days and repeat as neccessary.