Is it normal for an 8-and-a-half-year-old girl to begin breast development?

This situation occurs relatively early; it is advisable to visit a hospital to determine the underlying cause and assess whether medical evaluation or treatment is necessary. Precocious puberty is defined as the onset of pubertal development before age 8 in girls or before age 9 in boys. Therefore, the initiation of breast development at 8.5 years of age does not meet the diagnostic criteria for precocious puberty. It represents only a normal early stage of development, as sexual maturation typically begins only after the onset of puberty.