Well brother, congratulations for your decent performance in the both the formats of the exam.

Regarding your college, I wouldn't recommend oyu to join IIT. As you have almost nol chance of getting an old IIT with a decent core branch. 

So, I would strongly recommend you to opt for college on the basis of your JEE mains scorecard.

With this rank you can get any NIT, only difference would make would  be your prefered branch

Thank You