Dear aspirant hope you are doing well..

Yes you can do phd at any age if you fulfill the eligibility criteria for the exam. There are no age limit for doing phd.

The Most popular Ph. D exams are UGC NET, Joint CSIR UGC NET, JEST, JGEEBILS, etc

The required minimum qualification for admission to a Ph. D Program shall normally be a two years Master's OR M. Phil Degree from any accredited Indian or Foreign University in the relevant field. She/he must have obtained 55% marks or Equivalent Grade in the Master's or M.

Hope it's helpful..

Thank you