Are there age restrictions on TEFL?
There are no age restrictions on studying a TEFL certificate, or completing further study in TEFL. There are some countries which will not allow people over a certain age (sometimes 60 years old) to join their official English teaching programs.
It’s possible that if you’re an older applicant looking to get into TEFL, you could find it more difficult in terms of finding work. That said, there is no reason that you won’t be able to find fulfilling work in TEFL.