Graduation dress help?

ok so my graduation is this saturday and i have no idea what i am going to wear...we need to wear a dress that isn't to short or low cut and we are not allowed to wear heels so it has to look good with flats...i have no idea what girls usually wear to there graduation so links would be very helpful..and i am also a very quiet sporty girl that never wears skirts or dresses so nothing to frilly haha... i could use any help i can get thanks =]... links and pics are greatly appreciated