While I agree that whether Jill was staying there or not at that point of time is pure speculation on my part,the latter isn't.Looked to me like she was staying there. She was never a member of the Frat, so she would have no other reason to be there since none was mentioned in the narrative. There is also nothing stated in the game that she was a Freshman in that scene. That's just speculation.
Jill is currently a 3rd year which was stated in the scene where she met Josy,which means she was a freshman two years ago I.e. when she met Rusty,who was also a freshman at that time.