hello,The onset of breast development in girls less than 8 years of age may be the first sign of precocious puberty or more likely a condition referred to as benign premature thelarche. Benign thelarche is most commonly seen in girls who are under 2 or older than 6 years of age.In girls who are 6 years of older, benign thelarche or otherwise known as nonprogressive precocious puberty may be a consequence of temporarily increased ovarian steroid secretion and/or highly sensitive estrogen receptors. When breast development occurs without other signs of puberty in girls older than 6 years, limited work-up is indicated but monitoring of development and growth over subsequent months is necessary. Intervention is considered only if development progresses rapidly and there are psychosocial and final height concerns. 24kg for age is in higher range . plaese consult a genecologist to examine for the other signs of puberty, and to get hormonal level estimations.