No, actually 4 chances jan 2020,april 2020,jan 2021 and april 2021
You can give jee mains three consecutive years starting from year in which you are passing 12th.
Even if you don't want to give jee mains this year, just give it for the sake of it. At least you'll get experience. Whether you give jee mains in 2019 or not, you'll still get 4 more chances in 2020 and 2021