Hi Bhanu Prasad,

Ts eamcet is entrance exam  for students who want to do there graduation  in engineering and as per reservation they are going to provide reimbursement and  generally the validity for certificate is 3 years i suggest you to renewal it for safety , and based on your caste certificate and income certificate they will provide scholarship for you , so to avoid issues in future its better if you renewal now

Hope this information is helpful

ALL THE BEST