children start at very young age, my friend in New England is motocross crazy. His sons are like 4 and 7 taking part in dirt racing on kiddie motorcycles.
firstly you need to be born outside pak to be able to take part in such sports. or ask your parents to put you in school outside the country, otherwise its is very expensive sport if you try doing it here professionally,
if yr already a teenager you way too late for it.