Hey Pallab,

first you can go to the following link to estimate you rank by your marks! 

below is the rank predictor tool,

https://engineering.careers360.com/jee-main-rank-predictor

After getting your rank you can estimate your college by the rank! 

You can estimate the college by the college predictor tool.

Below is the predictor tool to estimate which college you will get,

https://engineering.careers360.com/jee-main-college-predictor

All the best!

Your expected category rank will be around 10,000.

Yes, you have chances to get NITs based on your rank.

To check which NITs and branches you can get you can use below JEE Main college predictor

http://www.engineering.careers360.com/jee-main-college-predictor