Nikhil, you haven't mentioned your Category. Neverthless, there is no eligibility aggregate criteria for appearing for JEE Mains. But for taking admission to NITs, IIITs and CFTIs through JEE Mains score, you need to secure a minimum aggregate of 75%. It is 75% for General Category and 65% for Reserved Categories. This rule also applies for JEE Advanced. Now if 69% falles in the top 20 percentile of your Board exams, then you are eligible for NITs, IIITs, CFTIs and JEE Advanced.