I am 54 and I have been teaching English in East Asia since 2001.
If your health is good and you are energetic, age is not a problem.
At first some elementary school students may call you "grandfather" but that blows over quickly as they get to know you.
Socially, if you are a drinker, that crowd is mainly under 35.
If you have health problems, health care and medication is expensive in this part of the world and medical insurance programs usually cover only a percentage of the cost.
Some people here are superstitious and believe that a sick person around them will bring them bad luck, so it's better NOT to talk about any health history.
Good Luck.