I'm not a woman, but I want to add to this discussion a little. Women, no matter your age, make sure you're checking yourself. If you think "it can't happen to me", you're dead wrong.
My little sister found a lump that she thought was a cyst. Turns out it was a mass of cancer 8-10cm. This was about a week before her 33rd birthday.
Docs may not want to do mammograms regularly that young. Who cares. You know your body best. If something doesn't feel right, get it checked. NOW.
"If you have something to say, now would be a perfect time to keep it to yourself." --Col. Chester Phillips
"If you believe everything you read, better not read." --Japanese proverb