Do twelve year old girls wear cupped bras?

It depends on how developed they are. The earlier you wear a bra, the higher your risk for Breast cancer. Here's some advice:

If they're not developed or just started.... A tank top or sports bra.

A-cups: Sports bra

B-cups: 100% cotton bra without an underwire

C-cups: Yes, wear a fully supportive bra, most likely with an underwire.

Nah....12 year olds should wear a cotton bra with a underwire it grips on to the breast more tightly im 15 i wear lace Bras sports bras are for 9 year olds