Well that was a motivational kick.
How tall are tall are you?
Your still young to be worried about that...around 14 to 15 most boys grow quite a few inches and around this time they put on a little weight or energy for the stretch up and is perfectly normal.
For as many experts thats say bmi this and weight that, there are just as many saying BS, let kids grow up first, schools dont help with do gooder teachers with half a brain cell...a little knowledge is dangerous ia a true saying!
Start doing some running or circuit training in your back yard but really dont worry!
Id wechat ?