Hi Prabhat! Firstly, if you secure 50% or above in your graduation, then you would be eligible to appear for CAT. Your 12th percentage is decent. There is no such hindrance to appear for the MBA entrance exams. Depending on the year of your graduation completion, you should start preparing for CAT and other MBA entrance exams. There are few top-tier institutes which do consider past academics, but now that you've already got the marks you can't do much about it. Hence, focus on preparation and completing your B.Com with a high percentage/CGPA.