Development at age 11 is normal. Puberty generally begins at the age of 9-12 for girls and 11-13 for boys. If secondary sexual characteristics develop before the age of 8 for girls and 9 for boys, it is considered precocious, so it is completely normal to start developing at the age of 11. The emergence of puberty reflects the acceleration of physical growth and development, the second growth spurt in life, during which time attention should be paid to ensuring that children have adequate nutrition and sleep. And in the adolescent children are in a state of emotional change and instability, often occurring a variety of abnormal psychological. Therefore, it is necessary to strengthen health education, sex education and health guidance for adolescents, so that they can achieve the overall development of moral, intellectual, physical, aesthetic and labor.