You can attempt JEE Main one more time in 2018.

If you want to apply for the application form you can refer below link

JEE Main Application Form 2018

To check the eligibility criteria you can refer below

- You must have passed 12 th class or qualifying exam in 2016 or 2017. Appering students can also apply.

- You can attempt JEE Main 3 times.

- For admissions to NITs/ IIITs/ GFTIs, candidates should have secured at least 75% marks in class 12th exam or be in the top 20 percentile in the class 12th exam conducted by the respective boards.

For SC/ST it is 65% marks.

To check complete eligibilty criteria you can refer below link

JEE Main Eligibility Criteria

Good Luck!!