Engineering Entrance Exam

Mahesh,
First, check this out what you have scored in class 12 as from this year The Ministry of Human Resource Development, Government of India has notified following two changes in the JEE pattern for 2017:
1. There shall be no weightage for the 12th class marks in calculating the ranks in the JEE (Main) examination,
2. For the candidates to qualify for the admission in the IITs/NITs/IIITs and such other CFTIs whose admissions are based on the JEE (Advanced)/JEE(Main) ranks, they should have secured at least 75% marks in the 12th class examination, or be in the top 20 percentile in the 12th class examination conducted by the respective Boards. For SC/ST students the qualifying marks would be 65% in the 12th class examination.
Another is what is the surety that next year you will get NIT only. What if you score less than this in JEE. Better would be to take admission in the college that comes your way.
In case you don't get a good college on the basis of these marks, don't go for some mediocre college. Opt for some of the good private universities like Lovely, Sharda, Chitkara etc offering various specializations in B.Tech.
All these universities offer world class learning atmosphere to students along with good placements. Some even offer good scholarships.
Good luck.