Just want to add my little advice to this topic and to those American Chinese (ABCs and alike) who are still able to communicate fluently in Mandarin. When encounter a native Chinese for the first time and you are asked "where are you from" in Chinese. Answering like "I am an American" is pretty much the same as saying “end of conversation”. It sounds puerile and defensive. The person asking this question probably knows you are not living in China and might have a US passport, so the question is just asking “what’s your or maybe your parents’ connection with China” more than anything else.