• underweight: below 2nd BMI centile
• healthy weight: between the 2nd and 90th BMI centile
• overweight: between 91st and to 97th BMI centile
• obese: at or above 98th BMI centile. This BMI centile

At the moment, you are around the 77nd centile for your age. This means if you were in a room of 100 boys, you would be the 77nd highest.

Without knowing your heights at different ages, it is difficult to predict accurately because I do not know whether you have always stayed on this centile or whether it is a growth spurt.

However, if you continue to stay on the 77nd centile, you are looking around 5'11 to 6 foot tall when you are 20.

No. A scale that is used nationalty works as follows. If 100 people are lined up - all the same age - then the 5th person is the 5th centile. the 50th person is the 50th, etc. Over all, anyone over the 50th centile is taller than average, and anyone lower is less than average. I am 25th, so I am a bit smaller than average.