It sounds like she just has a tight schedule...
Don't get discouraged because she already has prior obligations.
The best way to handle that situation is to find out what days she has available & make plans for one of them.
You don't want to bust on her too much for actually having a life... and at the same time, you don't want to come off looking like YOU DON'T have one. Ya know?
It's not Beta to ask what her schedule looks like... it shows initiative & confidence. AND.. you can actually find out the information you want.
A lot of guys feel like they have to make sure everything is set up on THEIR terms, rather than working with the reality that HER schedule probably isn't gonna be the same.
So I'd suggest you find out when she's available, & plan accordingly.