Hello Muhammad,
You should know that, your 12th marks does not matters for getring admission in NIT, IIT or any other state level government college.All that matters is your marks of JEE MAINS.If you want to get a good NIT college your rank should be under the required rsnk of that particular college. Only then you are eligible to get any college.It was happening till last two years ago that your 12th class percentage ware included 40% to get admission in different engineering colleges.