what I am give jee exam 2021 I am 12 qualify in 77 percent 2019

Hello Ankit!
As per JEE (Mains) 2020 guidelines, if you have passed your Class 12th in 2019, then yes, you are eligible to apply for JEE(Mains) in 2021, provided you have passed your qualifying examination with :
*For B.Tech./B.E. courses : Physics, Mathematics, Any one of - Chemistry/Biology/Biotechnology/ Technical Vocational Subject.
*For B. Arch. courses : Mathematics, Physics and Chemistry.
*For B.Plan. : Mathematics

There is no age limit for appearing in the JEE Main examination. This exam is conducted twice a year, and you may appear in both the attempts. A candidate can participate in the entrance exam for 3 consecutive years from the year of passing Class 12th/ its equivalent examination.
As you have got 77% aggregate marks in your Class 12th, you will also be eligible for IITs, NITs, GFTIs and IIITs (as the minimum requirement for them is either 75% aggregate marks in Class 12th board exams or top 20 percentile of your respective board, for General category). There is no such other percentage criteria to attempt JEE (Mains).

So, remember that 2021 will be the last chance for you if the guidelines for JEE (Mains) 2021 remain the as of 2020. You can participate in both the sessions - January and April. Make sure to not lose this opportunity.

Stay connected to us or keep yourself updated about the exam by visiting its official website : http://jeemain.nta.nic.in

Hope this answer will help you.

Hi

One is eligible for writing JEE Mains examination for three successive years starting from the year in which he or she has passed his or her class 12th board examination.

So, Yes , you are eligible for giving jee mains 2021 Examination as you have passed your class 12th board examination in 2019 . So you were eligible for JEE mains 2019 ,  are eligible for JEE mains 2020 and will be eligible for JEE mains 2021.

Thankyou