IIT

No, with 57 percentile it's not possible to get admission in any NITs IIITs or IIT. It's better to check for some other private institute which take students with their class 12th marks, as you have good percentage.

With 53 percentile, you cannot get admission in any of the reputed Institutes. You can only get admission in some Tier III Institutes in your locality for B.Tech.

There will be very less possibility that you get a seat in LNMIIT approximately there will be 99 percent chance that you will not get admission in LNMIIT.

Super 30 is the best, if you can qualify the entrance exam.

Yes, you can take admission in coaching.

Hello,
Yes, you can. There is no certain minimum age to appear for JEE exams. However for general category the age limit is 25 and for SC, ST etc. They have a relaxation of 5 years. For complete eligibility details, you may refer:
https://www.shiksha.com/b-tech/articles/amp/jee-main-eligibility-blogI

Hello,
Yes, you can. There is no certain minimum age to appear for JEE exams. However for general category the age limit is 25 and for SC, ST etc. They have a relaxation of 5 years. For complete eligibility details, you may refer:
https://www.shiksha.com/b-tech/articles/amp/jee-main-eligibility-blog

Why not, apart from getting admission in IITs, your success story will be published in top newspapers also. It's really good that a 16 year old student is clearing JEE advance. Also, you will be an engineer at the age of 20. It is really great, if you make it. Work hard. Nothing is impossible. Best