Hello Amrit

As nearly all the colleges give admission on basis of jee mains ranking ( except some)

And these exception conduct their own entrance or some give admission on basis of 12 th marks  .

And have a minimum criteria of 12 th also ( like for nits it is 75% for general) ; so with these marks it will be not possible then get into those colleges .

You can go in your city college or 

You should take drop and prepare for next year.( Both boards and entrace exam.)

Good luck.