Prom outfit

So my HS is hosting prom soon, and my prom date recently let me see her dress. It’s completely different than what I expected, not in a bad way, she looks really pretty in it. She chose to go in a sort of Ball gown, like the ones with poor and such. So now I wanna match her and go with something different. I only have a suit for concerts that i perform in and wanna look nice as well. What type of suits would you guys say would match her ball gown dress?