Body mass index (BMI) = weight (kg) ÷ height 2 (m)
Adult body mass index value:
Too light: less than 18.5
Normal: 18.5-24.99
Overweight: 25-28 years old
Obesity: 28-32 years old
Very obese,
Over 32 years old
It's only 1 1 years old now. Boys will still grow and develop at the age of 20, and they will definitely grow taller in the future. Don't worry about the weight.