I'm a former English teacher in my 30s. I primarily taught in China and somewhat in Vietnam, and all I have to say is: DON'T DO IT!
You will ruin your career and professional life. I went back home a few years ago and I've been trying to pivot into IT, but can't because I'm considered "too old" now.
If you are from a first world Anglo country, there is no reason for you to teach English abroad; it'll only be detrimental to your career. Maybe if you're from some Eastern Euro shithole and it's all you have to make money, go ahead. But Brits, Australians/NZ, Canadians, and Americans should NOT do it. You will get caught up with the easy girls, the easy lifestyle, thinking you're making money and progressing, then you'll hit a roadblock. Then, before you know it, you're 30 years old with nothing to show. You're also essentially teaching Asian people to come to your countries and take all the high paying 6 figure jobs. JUST. DON'T. DO. IT.