hey kuntal

As per the education quaificationyou need to complete your 10+2 and then you can go ahead with the exam.

Qualification Criteria:

For Army Wing of NDA: Candidates should have qualified 10+2 or equivalent examination from any recognized board.

For Air Force & Naval of NDA and 10+2 Cadet Entry Scheme at the Indian Naval Academy: Candidates must have passed 10+2 or equivalent exam with physics and mathematics subjects.

Candidates appearing in the qualifying exam are also eligible to apply.

all the best.

Hello,

Only if you have appeared or appearing in class 12 (10+2) examination then you can apply for NDA. 

To know more about eligibility criteria of NDA - Click Here

Thanks!