You scored 978 out of 1000 in your 12th board exams and have an 80.9 percentile in JEE Mains. SASTRA University offers admission in two ways: one based on a combination of JEE rank and board marks, and the other based only on board marks. Since your JEE rank might be a bit low for Computer Science through the combined way, your excellent board marks give you a good chance to get a seat in CSE or related streams through the board marks-only route. It’s a good idea to apply through both options to increase your chances.