Hello student as per the data you've mentioned you're 18year 7 month old so yes you're eligible for UPSC NDA because as per eligibility criteria candidates between 16.5year to 19.5 year old are eligible to appear in UPSC NDA.

Eligibility - For Army wing, Candidates must passed class 12 from a recognized board

For Airforce and Navy, candidates must passed class 12 in physics and mathematics from a recognized board.

Feel free to comment if you have any doubt

Good luck