No, it is not possible to pursue an MBA after your 3rd year of a BA LLB integrated course from a Mumbai University college as you need to complete your full BA LLB degree to be eligible for an MBA program.Since a BA LLB is a 5-year integrated course, completing only your 3rd year does not fulfill the requirement for an MBA.

Not only in this university but you cannot take admission to any master course before completing your b.a llb integrated course however you can take admission to bachelor's degree on the basis of your 12th marks.

I suggest you to continue with your course after completing apply to MBA anywhere in india.if you have time prepare for CAT exam which is accepted by iims and Mumbai University. Remember When choosing an MBA program, you can consider specializations relevant to your legal background, such as "Business Law" or "Intellectual Property Law" to leverage your existing knowledge.

To know about admission in mumbai university refer link

https://www.careers360.com/university/university-of-mumbai-mumbai