Hello Abhishek, you can take cs in engineering.PCM are enough for you to study cs.You need not worry that you did not study computer science in 12th.It is enough if you study sincerely while doing your Btech. in computer science

Yes yes you should surely go along with CSE. You will have to put some efforts and you will be able to cope up with it. It is a very good opportunity for you.

All the Best!!