I want to opt aerospace in either IIT BOMBAY or IIT MADRAS plzz anyone out there guide me i m in +2 ...

@ harshveet 
yes , for sure . kindly let me know what problems you are facing in jee prep and we will surely help u out . for opting for aerospace in iit , u need to frst obtain a qualifying percentage in board that is 70 for reservation people , and 75 for general people . 
and then u have to sit in jee mains exam , and then u need to qualify mains and attend advanced . 
in advanced , u need to be stay in top 1600 – 1900 rank to get this branch in top notch iits . 

ALL THE BEST ..