This is the One of questions Korean uttered while chatting with foreigners in Korea, even made me embarassed.
I think This is because of the confucism which need to respect older people otherwise it's assumed as illiterate or arrogant.
But please do not afraid or desperate when asking, but you can answer early in 30 or late in 20 something like that.

And then Next question would be are U married...
Do not misunderstand they're interested in you.
This is just question in Korea for a close friend or want-to-be without any other intention.

Next would be how many kids you have for married, or why you don't marry for single .
Please keep patient and appreciate to the guy asking for his kindness.
They're trying to find any agenda to talk or discuss about.
Any other strange questions in my country?
jz

He he It's very interesting post !
yes, you're right. But I aready know you dislike such that questions.
Most korean think as very important such age, marriage, children, family.
So, there are a good point and fault.

I noticed that too. Everytime you see an interview on TV, they will show that person's name and their age. I guess it's pretty important for Koreans to know your age.

Yeah, right. I don't know why. Actually, I dislike it.

Maybe that was an important thing to know for a person. Maybe they have some basis for that.