hlwo aspirant

hope you are doing good .

as you mentioned you got 64.6 percent in 12th so overall its okay. the minimum percent you need is 50 percent and you get more than that.

as well as you secure a good rank that there is high chance that in councelling you'll get iit, nit, vit, iiit and bit

Admission in NITs , IITs and VITs are totally based on your performance in JEE Mains. Though you must get 75% to be eligible for admission in all the NITs but these is no value of 12th class marks in gaining admission in NITs. Yes, getting a 1000 rank in JEE Mains is great to get you a seat in a government college,

hope this is helpful for you

best of luck