I would like to adopt my cousin

Hi. My name is Amy and I am 19 years old. I have a big problem and I need your help. My mother and my aunt died recently. I have father, but I have realy bad relations with him. My uncle is a soldier and currently no one knows where he is. Or if is he alive. I have a cousin, girl - 2,5 years old. I can't let her to live in some foreign family. She needs to be at home, with someone who loves her. And someone who knows her. Could you give me some advices? I have no idea what's gonna to happen. Please tell me what I have to do. I live in San Francisco, in small flat, which I shared with my mother and it's mine now. I have some money and I have a job too. I am her closest relatives. Can I adopt her? Or what? Can she live with me? Please, tell me everything. Please quickly.