if dont get. good percentage in 12

Patil, you haven't mentioned the subjects you are studying in your 12th. Neverthless, if you do not get a good score, which happens with half of the students who appear for their boards, you can appear for Improvement exams. That way you can improve your percentage. But if your marks are not sufficient enough for admission to courses in Premier institutions, you can visit the article http://cbse.nic.in/newsite/attach/Compendium%20of%20Courses%20after%20+2.pdf and check the courses that you can study based on your subjects from your 12th. This is a list designed by CBSE and it also has the list of Institutions that offer these courses. It might help you to determine your future.