Hello Kshama kumari,

If you get 69 marks in JEE mains exam ,then the you overall percentile is nearly 90.27 - 90.47,  and the rank is nearly 87638 - 104788 .if your marks are more than the cut-off marks and you have  changes of getting the seat in NITs college and also you are eligible to write the exam of JEE advanced  and the percentile and rank can be calculated by using the percentile/rank predictor which is available in the below link.,

Hope this helps  you...