Hi, so basically MCA as in Master's Of Computer Application is a 2 year course that teaches computer science.

NIMCET is an exam that us required to get admission in top MCA colleges such as NITs i.e., National Institute of Technology.

There are the options of private colleges too but if you want to crack a good gov. college such as NIT then you would have to clear the NIMCET exam.

And to take admission in a MCA college you have to complete your graduation first.

If you are gonna complete your graduation this year then you are definitely eligible for MCA exam.

Hope this is helpful