For AIRFORCE through CDS 2, the age limit is that you must have a age within the range 20 to 24 years. If you are born on 1999, then your age will be 23 years. So you are eligible for the CDS Examination.

The eligibility criteria for the CDS (Airforce) is provided below:

Bachelor's Degree from a recognised University (with Physics and Mathematics at 10+2 level) or Bachelor degree in engineering.

To know more about CDS Eligibility criteria visit the link below:

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

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