Here's an overview of the major physical changes girls can expect as they go through puberty:. Girls usually begin puberty between the ages of 8 and 13 years old. The earliest sign of puberty in most girls is the development of breast "buds," nickel-sized bumps under the nipple. It is not unusual for breast growth to start on one side before the other. It's also common for breast buds to be somewhat tender or sore. Uneven breast growth and soreness are both totally normal and usually improve with time.

It starts with a firm, round, tender lump called a breast bud under the nipple of one or both breasts. Girls may complain about feeling sore when they sleep on their stomachs; parents occasionally worry about the lump being a cyst or tumor. One side may develop considerably faster than the other.

This usually starts when a girl is about 10 years old. Sometimes, though, a much younger girl starts to show the signs of puberty. These early signs of puberty can be hard for your child.