It is really great that you have chosen to serve your country which is really a proud thing .Here I have mentioned all the details you must be aware of.
For Indian Air Force:: 19 -23 years.
For Navy ::19-22 years.
For Indian Military ::19-24 years.
**If you have Intreast you can Join in Indian Military Academy.To Enter into this criteria you can appear the CDSE.
CDSE(Combined Defence Service Examination).It is held by UPSC every year two times.
you should be complete the graduation from recognized university with out any Back logs.
you should belongs to Indian.
Male and Female Both are eligible.
you should be Unmarried.