hello lovely ladies (and gentlemen...?)

,
i will be interviewing for a prof. sorority in a couple of days (once rush is over, i will post my story in rush stories as i said i'd do a while back!), and today, i realized i hadn't brought anything "formal" to college beyond a summer sundress and a couple of jackets!
so, question.
can i just wear a jacket + heels + sundress to the interview? would that be formal enough or too much like i'm going out clubbing?
replies are much appreciated.