To be eligible for NDA a candidate must have born between July 2, 2002 and July 1, 2005. The age of the applicant must be between 16.5 and 19.5. Check if you have fulfilled the age eligibility requirement. If you have fulfilled it then you can apply for NDA 1 2021. You must have also passed 10+2 with Mathematic, Physics and Chemistry from a recognized board to be eligible for INA and AFA and for IMA you must have passed 10+2 in any stream. You can apply for NDA using the link below
For NDA application age limit for unmarried male candidate is 16.5 years to 19.5 years. Candidate must born between 2nd July 2002 to 1st July 2005 for NDA I. And NDA II candidates must born between 2nd January 2003 to 1st january 2006. This is the age limit of NDA.
No 11 class student get NDA examination. Your qualifications must be 12th passed.
Hope this helps. All the best.