Hello. My name is krishna. I've completed my intermediate in 2019 and i didn't gave any attempt to jee ( Mains & Advance ) in 2019. And now I decided to crack jee mains and advance. So, what my doubt is, Am I eligible to write jee main and advance examination in the coming years 2020 and 2021.

Dear aspirant, yes you are eligible for JEE MAINS 2020. I am not sure about 2021 as the eligibility criteria for JEE mains 2021 hasn't released and since the exam pattern has changed this year who knows what changes NTA will done. For now, Candidates who have passed class 12 or any other equivalent exam in 2018 or 2019 or those who will be appearing in class 12 or any other equivalent examination in 2020 will be eligible to appear in JEE Main 2020. Those who have passed class 12 or equivalent examination in 2017 or before and those who will appear in 2021 or later will not be eligible to appear in JEE Main 2020.
All the best
Hope this helps