Am I too busty for a strapless dress?

Basically, I'm 17 and I have a formal event coming up. Most girls are wearing those shorter, strapless dresses with ballet flats. I'm 5'6 and weigh 135 lbs, with 32DD breasts. Am I too busty to go strapless? If not, where in the world can I find a strapless bra that'd fit me?