Hi Dear,

YOu can get into Indian Institute of Science (IISc) and  Indian Institute of Science Education and Research even after completion of your 10+2 from physics, Chemistry, and Biology stream. You do not need to repeat your 12th class for this purpose. You can either enroll into undergraduate research programmes now or you can also prepare for integrated PhD and MSC course from IISC and IISER after completion of your graduation the same field.

Good Luck