Why hasn't she replied to my text?

So this girl and I have been dating for a month now. I'm gay, she's bi. I really like her. We're both pretty busy. She joined a sorority last week, has a job and goes to school. I'm in school, have a job, doing things in clubs at school. She's a little flighty at times, and she's not a definite answer person, esp. if i try to make plans several days in advance. I called her sunday and we chatted for an hour. Monday, I asked if she wanted to go out and have dinner,etc. She said "Yes of course." At first, but then she said, "but wait.. i get out of cl wens and thrurs at seven pm. But i might have a sorority meeting after idk. Can I get back to you?" I said ok. I text her today if she knows her schedule for the next couple days. No response. Does she seem interested? Would an interested person do that? What do you think is the reason she hasn't responded to my text? I'm not bombarding her with texts and phone calls or anything...