Why did many Americans ask me "how old are you"? Especially males
It's sometimes okay to ask people their age. If someone is young, like less than thirty, it's usually fine. Or if you know them. I don't usually ask 30+ year olds unless I know them, because some of them are sensitive about their age, but I wouldn't say it's very personal or a secret. I am willing to tell anyone who asks.
That said, it's a little weird to ask a stranger. And it's true that sometimes when a man asks a young woman her age, it's because he wants to know if it's legal for him to have sex with her. But other times the person asking is just curious or trying to make small talk. If it makes you uncomfortable, you can say so. Most people will respect your boundaries, and you dont need to talk to the people who don't.
I don't usually care about person's age, If I just having a conversation with that person. But, often, people tell something smart or some astonishing facts about them, I just cant stand it to ask about the age. And when I find out that the person is young enough comparing to his/hers age, I feel like "wow, so young and so smart" or "damn she's only 23 and already done some many things! She has to be so purpouseful...". After all, this person becomes even more interesting to me. Anyway, I don't think that ones should be afraid to tell age, or consider that it is a rude thing to ask about it. Good people just getting better when the get older, remember that :)