Dear Piyush ,

There is no limit for attempts National defence academy but age restriction is there ,so you should maintain that such as basic age criteria 2020 NDA .

The candidates whose date of birth falls between 2nd January 2002 and 1st January 2005 are eligible. The date of birth as in the Matriculation/Secondary School Leaving Certificate or in a certificate recognized by an Indian University as equivalent to Matriculation will be considered.

Apart from that This age factor restrict you to basically max. 5-6 attempts. There is no embargo on number of attempts but till the time you are eligible for the examination,

I have share a link with you where you will get all the necessary information .

https://competition.careers360.com/articles/nda-eligibility-criteria

Hope it will helpful

Thanks