Go to a Pink by Victoria's Secret store. It's geared for young people.

First of all you have adult size. Second thing the exact bra size will be as per size measurement. My size is 30 D. Mostly I purchase trendy & designer bras & lingerie from eliraphael. Fashion reflects a thing that what style you really has.

if I grab your boobs, they will be even bigger. :)

so you are a 12 year old walking pair of boobs.