Hello shubham.

Well,from this year NTA is conducting JEE mains twice a year,once in january and another in april.Don't worry,you can still practice for april session.You got 2 months to practice.The best way will be to dedicate yourself towards studies for these 2 months and score well in april session as the beteer score of two will be considered.Hence,start studying.Hope this helps

Good Luck!