There are certain criterias that the candidate has to fulfill to be eligible for JEE Adnvanced. 

• Candidates appearing for JEE Advance must qualify JEE Main and secured a position among top 2,24,000(for 2019).
• From this year, candidates of age more than 25 years are also eligible to apply for JEE.
• A candidate gets maximum of two attempts in consecutive years to appear for JEE Advance.
• The first attempt will be the year of appearing for 12th examination i.e, in your case 2020.
• The second attempt will be in 2021.
• The candidate shpuld not have been admitted to any IITs irrespective of whether he/she continued the programme or not.
• The candidate should have passed 10+2 with an aggregate of at least 75% marks (general and obc).
• For SC/ST, they need minimum 65% marks.