Feeling of interview

Different people have different opinion. When I ask my friend and my teacher about what topic is acceptable in American, I get some interesting answer. All of my friends think politics is acceptable topics, it's different with book. Besides that, some of my friends think religion and age can't be unacceptable topics, but they think income is acceptable topics. One of my friend thinks religion and age is fine to talk in small talk. So, all the above, whatever you want to talk, you should ask your friend first,could i ask something about XXXX.
If you travel to my country and you get small talk, you shouldn't talk about your friend age, I think it's impolite in China, because the reason is depends on my culture, we don't ask peoples age before you make a close friend. AND, do not ask lady age, if you do that, the lady will not want to make friend with you.