What is the earliest age at which you can get breast cancer?

My youngest 18-rare: Though we can see unusual breast malignancies (sarcomas) in the pediatric / adolescent age groups, the usual epithelial based cancers, that you would know as infiltrating ductal or lobular carcinoma, are in older women. As a guideline- less than 5%of cases are under 30 yo, increasing from there with each decade. Genetic mutations (brca 1 or 2) would shift the curve toward a younger age of onset.

Rare: Breast cancer in teenagers is rare but can happen. The average age for developing breast cancer is 65.