According to the Centers for Disease Control growth chart for children age 2 years and older in the United States, the average weight of 15-year-old girls is about 115 pounds or 52 kg. The chart indicates that the weight ranges from 85 to 180 pounds, depending on height.
To know if one's weight is ideal, CDC recommends using a BMI calculator. The BMI, or body mass index, is an indicator of body fat, and the calculator results are used to screen for overweight and obese children 2 years old and above. The BMI calculator is not a diagnostic tool of obesity because additional assessments are necessary to confirm the condition, the CDC cautions.