I find your supposedly-serious girlfriend suggesting 20 questions to be an incredibly immature way to lure you into a false sense of commitment. I'd like to ask if your are perhaps in middle-school, because this is a very sophomoric play if you envision yourself in a serious relationship with a loved one. 20 questions is a method for those unaquainted with another, not for a committed couple. But if you would like to go through with your girlfriend's request, take a clue from Playboy's 20 Qs and keep it
real. Good Luck.