I would avoid the folding bike...college kids tend to think they're kind of nerdy. A step through frame or mixte is definitely more accessible to a beginning female utility rider.

Thinking back, 18-22 year old me (with absolutely no knowledge of anything having to do with bikes) rode less than I should have because of (1) brakes in need of adjustment, and (2) messed up gears (adjustment problems, as well as broken derailleurs due to throwing the bike around.) If I'd known how to adjust my brakes or had a coaster brake, and rode a single speed, I probably would have grown to love bikes much sooner.