To women, how do you feel if someone ask you that question ?
I don't know if that is a rude question in your countries or not but it is totally no problem in my country.
Especially, on Tet holiday, my relatives even ask me more personal questions such as
" How much is your salary ?", " Why aren't you married yet? " and so on.
So if you come to my country, you had better prepare your answers. ^^
Of course, not all elder people ask questions like that.
Those questions are considered quite personal. I would feel uncomfortable answering them if I did not know very well.
In Slovakia in general it is considered as an inappropriate question, but it often depends on circumstances. As for me, I don't mind being asked. Everybody can see how old I am in my profile. It is just the number. Each period of life is great whaterver it is.
In my country "Iran" sometimes people ask personal questions like "why dont u get married" or even "why u get fat" or something like these! of course many people dont like to answer... I see these kind of questions usully by older people or relatives. and youngers mostly consider it rude.
and about the age.. we also use "which year was you born" its a common question and it is not very rude although some women don't like to answer...