Typically, puberty begins in girls at about the age of eleven or twelve, but can start as early as the age of eight or as late as fourteen. Puberty in boys usually begins about six months to one year later than in girls. The first signs of puberty in girls include the beginnings of breast development, significant increases in height and weight, acne, widening of the hips and the initial appearance of pubic hair. For most girls an increased interest in boys also accompanies the onset of puberty.
Girls usually have their first menstrual period about two years after puberty starts.
The final stage of puberty, in which a girl's breast development, pubic hair development and full height is reached is most often completed by the age of fifteen, but may not occur until the girl is nineteen years of age. Early bloomers, who begin puberty at a younger age, often have problems with being teased in school, and may gravitate toward the older teens that they physically resemble more than their peers. This is almost always problematic in that the younger girl is usually not as emotionally mature as her older counterparts and often has a more difficult time making age-appropriate decisions regarding her behavior. These girls may also be unprepared for the changes that are occurring in their bodies and especially for having their first period. Girls who develop later than the average may also be teased by their peers.