Hello student,

The CDS exam is conducted twice a year by Union Public service commission. It is held to get recruitment into Indian military academy, Indian Naval academy, Indian Air force academy and officers training academy. The age limit for IMA and INA is 19-24 years, for air force academy it is 20-24 years, for officer's training academy it is 20-25 years.

For more information regarding the CDS eligiblity you can use the following link:

https://www.google.com/amp/s/competition.careers360.com/articles/cds-eligibility-criteria/amp

Hope this helps.