Well brother, I can understand your situation. I know you have worked hard for JEE mains but I believe with 12.1k rank you won't be getting college with CSE branch. 

Though with EWS and home state quota, there might be an increased chance of your's getting a seat but with such a rank it is very hard to get.

So, I would recommend you to take part in JoSAA and go to through all the round even the spot round.

or the better recommendation can be

to prefer Thapur. It is one of the older colleges in education industry with better Alumni than many of the NIT's. 

Thank You