If she were enrolled in a course he took he wouldn’t have to ask why she attends, so she’s not. I think “what are you doing at this university” works the same way; not necessarily, but of course she says “I serve chips” not, “I study physics/poetry/etc.”
So I think she’s not. Maybe she doesn’t have enough money to. Maybe she’s serving chips and saving up while sitting in on lectures at the university she’s always wanted to go to, dreaming and working for it, even before we meet her.
I love her already.