Stage 1
Age 0-8
The preadolescent breast consists of a small, elevated nipple with no significant underlying breast tissue.

Stage 2
Age 8-14 (usually 11-12)
Breast bud stage; elevation of the breast and nipple as a separate small mound; the areola (the area around the nipple) begins to enlarge, and milk ducts inside the breast begin to grow. This can often be an awkward time for a young girl as she starts getting used to the changes.

Stage 3
Age 9-15 (usually 12-13)
Enlargement and elevation of the breast and areola (less separation), the areola begins to darken in color, and the milk glands begin to grow. This is the stage that a girl may consider buying her first training bra.

Stage 4
Age 10-16 (usually13-14)
Projection of the areola and nipple to form a secondary mound. At this stage a young girl may need to start using a bra with cup sizes.

Stage 5
Age 12-19 (usually 15)
Mature adult breast, projection of the nipple. Now the breast growth is complete, however breast never stop growing, or changing. These stages are used as a guideline for breast development, but all girls develop at their own unique rate. For more information about bras, breast developments, and bra sizes, please visit http://www.myfirstbra.us.