Parental permission for someone under the age of consent.

Hi,

I'm 24 and from the United States and my girlfriend is 18 and from Chongqing, China. We met while I lived in Chongqing last year and have very recently decided to get married, but we do not want to for her to turn 20 as I need to start my job back in the States.

I haven't heard or read about this parental consent anywhere else online so far. Can you tell me more about it?/ Do you think it is possible for us to get married in China while she is 18 or 19 if we submit the parental consent form?