NIT

Just focus on your studies from 2nd year, and after 3rd year you can join coaching for GATE preparation, specially focus on discrete maths, data structures and computer organization and architectures. (COA). And, perform well in GATE.

12th marks are important. Your marks play a key role in letting you to nits n IITs, but there is a chance of getting into NITs and IITs if your JEE Mains and Advanced marks are extremely good.

Yes, NIOS board is applicable for admission in IIT or NIT.

The best colleges for automobile engineering in India are-
1. DTU
2. NSIT.

Some best engineering colleges in India are-
1. VIT
2. BITS
3. SRM
4. Manipal.

You have a good future don't worry. Just go for the competitive examinations and study well.
All the best.

Hello Shivani,
Just after class 12th (science), you will be eligible to take JEE Mains & Advanced after clearing these test, you can join BE/B.Tech.
Good luck.

No. There is no lateral entry for IITs and also for NITs.

There is no other option to get admission in NIT without taking JEE Mains for engineering. So, it would be better, you should go for it and for OBC category, safe side would be around 155-180 to get a seat in NIT. So, go for it. All the best for future.

For admission in NIT, candidate must appear for JEE Mains. Unless you appear for the entrance exam you won't get admission in National Institute of Technology. The eligibility criteria for entrance exam is 12th with PCM as the subjects. Apart from IIT and NIT, most colleges in India offer lateral entry for Diploma students. These colleges do reserve some seats for lateral entry students.