NDA 2020: The candidates possessing age between 2nd July 2001 to 1st July 2004 are eligible for the examination. The minimum age limit to be eligible for NDA is 16.5 years
If the candidate bears the age before 2nd January 2002 and after 1st January 2005, they are not allowed to appear the exam.
So you Cannot appear for the examination now.
You can appear in the year 2022 .
Best of Luck for your future!