Hello there!

There's no attempt limit for GATE examination so you can appear for gate exam as many times as you want but you should work hard and try to clear it in the 1st or at least in the  second attempt.  If you are going to appear for GATE 2020 then I would like to tell you that GATE 2020 exam is going to be conducted by IIT Delhi  . Online registration for GATE 2020 is going to start in the month of September 2019. Also there's no age limit in GATE exam,  so you don't need to worry about that as well.

To have detailed information go through :- https://engineering.careers360.com/articles/gate-eligibility-criteria

Thankyou