Hello aspirant, 

It would be more helpful to provide you with appropriate details if you have mentioned details more precisely as your score or percentile. However if your ultimate goal is IIT and you missed it now with just narrow score and you are very much confident about yourself that you can crack it for sure next time then go for long term else if you got seat in top colleges in the stream you are aiming for then you can even excel your skills there.. because the classes that are being taught in IITs can be even available for the students who are not IITians through websites provided by the central government. So instead of wasting an year when you are not confident you can go for this and later you can crack gate exam and enter into IITs. 

All the very best for your bright future!!