hello swamiharish

I hope you are doing good . I would glad to inform you that you can jee main in 3 consecutive years from the year which you have passed your 12th .  You have done your 12th in 2019 , then you can jee mains in 2019 ,2020 and 2022 . SInce, jee mains is now conducted 4 times a year , so you can give exams of jee mains and jee advance 4 time in 2020 and 2021 each .  For you information , their is no age criteria

Hope you found this answer helpful. Good luck for your future