I am in class 10th cbse I want to do iit what score should be getting in class 10th 11th and 12th and after 12th what should be do

@ raman 
class 10^th dnt have any relation with jee prep . 
just make your concept strong in class 10^th , and obviously a cgpa more than 9.2 is more preferrable . 
and in 11^th itself u need to start your iit preparation , 
and after 12 u need to write jee mains exam , and after qualifying that u need to write jee advanced exam . 
and if u can get agood rank in jee advanced exam , then u can join iit after that . 
ALL THE BEST ..