About American green card (cousin is an American citizen)

It's not impossible. It just takes a very, very long time to apply. First, your cousin wants to apply for his parents to go to America, then his parents apply for your parents to go to America, and then your parents apply for you to go to America. It will take decades. So if you want to live in America for a long time, I advise you not to waste too much time thinking about your cousin.

The quickest way is to marry the wife or husband of an American citizen (for reference only, after all, it involves your lifelong happiness, think clearly).