I have small and it makes me sad?

I'm almost 21 years old and i'm a pretty small person and people always think i'm like 15. There is nothing much I can do about the size of my hips or my height, but is there any way I can make my bust a little fuller? I've heard doing push-ups and exercises for your pectorals can help as well as taking certain herbs in conjunction (like fenugreek, saw palmetto, etc.). Have any girls had any success with this?