Hi guys, I'm new here

so I met this really pretty and really nice girl in my class, she is really humble and just a nice girl and looks good! I wasn't really interested at first since I didnt know her but we kind of got to know each other during the semester we don't really talk that much mostly just small talk about the class and hi/bye. So last week at the end of this semester I saw her waiting for a friend so I just walked up to her to talk to her, and oh my gosh she is soo nice and we really got along good. Since I don't have her phone number, I messaged her on Facebook instead starting of with a little small talk about the grades in that class and then asking her if she wants to hang out next week. She didn't immediately reply like the messages before but like 30 min later with: yea if she has time cuz she works over the summer.
What can I interpret in this answer is it more like a no she doesn't really wants to meet up don't wants to be rude or am I over thinking?
Oh and a little more general infos: I will only have time next week cuz I'm moving in a new apt. And I don't have a car so I can't really take her out

only places withint walking distance. I'm 3 years older, I think she is 19 and I'm just little bit taller then her.
Just wanted to let you guys know in case that matters. Oh and yea I'm looking for a relationship

oh and I only have 3 weeks left to meet up with her cuz after that I'm on vacation and the next time I see her would be next semester which is end of August!
If you guys can help Me that be really nice.
Oh and I don't know if I'm writing this in the right section of this forum if not, sorry. I wanted to put it in another section first but it said no newbies.