I came to US on student visa and have been here for almost 2 years now. I have a girlfriend here in United States who is of caucasian descent(white). I was wondering what process do I need to follow to get married to her(court marriage) and get the US citizenship or at least a legal work permit. How much will it cost altogether and how long will it take?
Personal: I have yet to ask her to get married but I'm kinda sure if I ask her she will say yes. Also, if it is important, she is a high school graduate and she currently works in a restaurant as a waitress and attends a community college.
About me: I will be 20 years old in 4 months and she is like 3 months older than me.

Thanks.