The prerequisite for having a passport from a certain country is that you have the nationality of that country. U.S. citizenship is a far cry for you; the first thing you need to think about is a U.S. green card (permanent residency). With a green card, you can live in the U.S. for a few years before you can consider applying for naturalization. Naturalization is optional; you can be a permanent resident forever. Chinese citizens automatically lose their Chinese citizenship if they voluntarily join a foreign country.
After you get married you will have to apply for a green card as the type of spouse of a U.S. citizen.