I need a gorgeous dress.Help!! school Farewell coming up....and the theme is ballroom..?

I have my school farewell coming up n I am planning to wear something of knee length (i don't want to wear a gown) along with a tiara. I am an Indian with straight black hair, dusky complexion. I am quite thin.My waist is 23 inches . My height is about 5 feet 3 inches. Please help me find a gorgeous dress