I have the same problem O-O"
I do modeling,and EVERYONE in my class have a big bust,have their periods and stuff.
My mom said that a HUGE bust makes you ugly and some boys won't like girls like that :kusatchi:
When I was during my photoshoot,when I was going to get my swimsuit pictures done, I saw everyone with a big bust,and me? FLAT-CHESTED (well,not that flat xD)
And as TamaMum said,athletes (sp?) usually have a small bust,just like me,I am a bit happy for having a small bust,because my ballet teacher said that I have a perfect figure for ballet :^D
PS- Don't feel bad about it,personality is much better than body image
*points at modelling girls....*