While there is no upper age limit for appearing in JEE Mains, there is year of passing limit. For example, to appear for JEE Mains 2021, you should have completed your 12th either in 2019 or 2020. Those appearing for their 12th in 2020 or 2021 are also eligible for JEE Mains 2021. But if you have completed your 12th in 2018, unfortunately you are not eligible for JEE Mains 2021.

Dear Candidate,

Let me tell you that, every student got 3 chances of JEE Mains . The one chances you have wasted in 2018. And your other 2 chances had completed in the year 2019, and 2020. Hence by now, you have zero chances left for JEE Mains Exam. So, you are not eligible to give the JEE Mains exam 2021.

Hope it helps.