While at the market the other day I spoted a girl that I went to high school with. I only had one class with her senior year, so we were some familiar with each other. At the time I didn't go up and say hi, this made me feel shitty,so I sent her a message on Facebook. I made up a story about something I saw and it reminded me of her and things she said in the class. We jokingly message back and forth, eventually asking how each other is doing. I ask her it she would want to hangout before she has to return to school from winter break. She says she's pretty busy but we can arrange something. She says she's free on wednesday and sunday, eventually leading to Sunday being the better day. I tell her we can meet up or I can go to her. She hasn't replied since. This was on that Tuesday and it's thursday now. Should I write back or wait?