The physiological development process of adolescent girls

The onset of sexual maturity in girls is almost always marked first by the development of the breasts, with the left breast typically developing before the right. The breasts begin to swell, there is pigmentation around the nipples, and the areolas expand outward. Prior to this, the sexual sensitivity of this area is roughly the same in both boys and girls; however, now for girls, this sensitivity starts to increase. "Breast buds" usually appear around the age of eleven, but they can form as early as eight or as late as thirteen. It takes about two and a half years for the breasts to fully develop. Whether a girl embraces or conceals these changes in her breasts depends on her personal attitude, as well as that of her family and friends.