Can i do bba then mba after 12 by taking scince stram?

Yes, 12th science stream students are eligible for BBA & then MBA. But you need to score well in your 12th for BBA & in BBA for MBA, as may universities have some cut-off criteria for admission. I would suggest you to opt for unique specializations like fashion, retail etc ..these fields have better job opportunities than those conventional programs. UTM Shillong is one such university that offer such kinda courses, you can check its website to know more about the courses.