The average height of a 13-year-old girl in the United States is 61.7 inches. Girls commonly experience a growth spurt between the ages of 10 and 14 years old. During that period, the average height increase is 8 inches. Genetics and race also affect a girl's expected height.
At the age of 13, the average height estimation for girls exceeds the height estimation for boys by 0.2 inches. However, by the age of 14, the average height for boys exceeds the average height for girls by 2 inches. At the age of 19, the average height for girls peaks at 64.3 inches tall.