Hii aspirant..

Eligibility for GRE exam is -

There is no prescribed age limit or qualification required for candidates to appear for GRE 2019, however, since GRE is an assessment test for admission to graduate courses, candidates are expected to have successfully completed their undergraduate program. 

Thus, if you have successfully completed your undergraduation then you are eligible for GRE exam.

And after qualifying the exam you can get admission in your desired college and course. 

Hope it helps. 

Best of luck.