assuming you mean teach english as foreign language then yes I did it when I was 19 in China.
I got the job through a site called daves efl cafe
The hardest part is getting a visa the jobs are thrown at you when you are there
I got a visa through an agency who said they had a school position for me but when I arrived the school withdrew the offer so I phoned another agency and they had 30 or so positions for me to choose from because I already had a visa and in the country!
I got paid 10,000 yuan a month and they provided accommodation and taxi to the school
I really need a change and this idea came into my head, anyone done it, i am in 30's but still probably look and act about mid 20's not that that should be a factor.
I need more roofies before I can do Tefal...
Age is fairly irrelevant for it, I know people anywhere between 19 and 60 doing it. It's a great way to travel, and in China in particular you can pick up a job just by being English, but you're best of with a qualification if you want some sort of choice in the job you take. I'm leaving for Taiwan in a few weeks to go start a new TEFL job over there, just seemed a more interesting place to do it than carrying on with private classes with the couple of students I have here, and it'll make a change to not just teach Spanish people.
Have done it in China previously too, "well behaved" very much depends where you're teaching - my ex was taking classes of 60 people in a middle school, a lot of whom would just sit playing on their phones and completely ignoring her. It can be incredibly rewarding, but it is a responsibility too.
I need more roofies before I can do Tefal...

Finished doing CELTA last month, and currently on the hunt for a job. My advice? Do a proper course (CELTA or Trinity TESOL).
Much better prospects, and the course is really very good.
fifiov also did the CELTA course IIRC, in Edinburgh. It costs between £1000-£1200. However, it's only one of two that are accredited (by Cambridge for CELTA) and has a worldwide reputation.
Lol
It's wrong but I was thinking something similar