I got 43% in +2. I am doing BCA. Can I do MBA in a big college?

Yes, definitely you can do for getting in one of the top MBA colleges. You should have at least minimum 50% in your graduation, which is eligibility criteria for most of the colleges and score well in exams like CAT MAT CET at least above 90percentile.

You need to ensure that you score more than 50% marks at the graduation level. Prepare for CAT common admission test) for MBA and try to score more than 90 percentile to seek admission into a good big college.