Pubertal Buds

• Puberty will normally begin in girls around the ages of 8 to 13. Breast development at this time will be in the form of a small "bud". This is just a small bump on the chest behind the nipple.
  
  

Bud and Continued Growth

• During this stage, the breast bud continues to grow in size and shape. Inside the breasts, milk ducts are growing along with fat deposits. Estrogen production has started during this stage.
  
  

Further Growth

• In the third stage of breast growth, fat continues to be deposited and the breast shape becomes fuller and rounder.
  
  

Separation of the Nipple and Areola

• During this stage, the nipple becomes a separate mound from the areola. Some girls will skip this stage and go directly to the final stage of breast growth.
  
  

Final

• The fifth stage of breast growth is the final stage. The breasts at this point have a fuller and rounder shape due to the full development of the glands inside the breasts and the deposition of fatty tissue.
  
  

Ages

• Just as there is no exact age that puberty begins, there is no set time frame for these developmental changes to occur. Some girls will develop their breasts very quickly and some will take more time. In either case, most girls are done developing around five years after puberty has fully kicked in.