MBA and LLB both are two completely different fields. It's more over depends on your interest in which field you want to pursue your career.

If you look to pursue your career in MBA then you need to clear CAT exam and then go through interview process. It's a very tough process which involves all your 10th, 12th, graduation marks along with your work experience (If you have any, not necessary for selection).

MBA will take you into the corporate world in which you have lots of potential fields to grow yourself whereas LLB will take you into law field which is completely different.

As you have done b.com so you have a prior knowledge which will definitely help you while pursuing your MBA degree. That's just a piece of advice from my side but in the end decision is all yours where you want to go.

MBA field is attractive and you will have a very good chance of getting a job with fat salary if you will pursue it from a reputed college. I myself is doing MBA from IIM Kozhikode, if you need any more details about it then you can reply back here.