This is the age limit for 2021:

Candidate should be born between n 16 January 2001 and 29 December 2004 (both days inclusive. In case, a candidate clears all the stages of the selection procedure, then the upper age limit as on date of enrollment is 21 years.

So if you study that then you will have 3 attempts as you will turn 21 in 2023. So the attempts you can have: 2021,2022,2023.

I hope my answer helps. All the very best for your future endeavors!