Hello Gautam, 

Since there is no age limit in jee main to appear but there is one condition if you are appearing this year must pass in  2017 and  2018 in class 12 

i am providing you with a link which would help

https://engineering.careers360.com/articles/jee-main-eligibility-criteria

There are 3 chances for everyone to appear in Jee main. One when you are appering in class 12th then other when you passed class 12th and the last chance is after that year. Suppose that in 2018 you are appearing class 12th then you can give exam in year 2018, 2019 and 2020.

Hello Aspirant,

No, you can not appear for Jee mains if 2 years have passed since you cleared your 12th. You can only have 3 attempts, considering attempting of the two sessions of the same year as one. The 3 attempts can be the year of your passing, the next year and the next to next year. After that you will be ineligible. 

Hope this helps!