hey subhasis!

bsc computer science is an excellent course to do after 12th .yes you can surely do bsc computer science at this percentage .while it is difficult to get computer science in a college which is taking admissions on the basis of merit you can surely try some colleges which is taking admissions by taking entrance exams and there is no shortage of such colleges all it depends upon state in which you are seeking for admissions .check out list of colleges in your state where entrance exams are conducted . like if you are in up then bhu ,amu,integral college are some good examples 

best of luck