hey there banhaneul and welcome!
there is
a similar thread. have you seen it yet?
I definitely agree that a lesson with this subject would be great!
In my limited experience, most of the questions were about me - like a lot of questions. I'm not used to being in the spotlight so it can feel a little much.
Depending on their English speaking ability, your girlfriend will probably do most of the talking for you. All in all, make a good impression by being polite, using honorific speech, and speak when spoken to. I'm sure that when they see your interest in the culture and language, they will be that much more receptive to you.
...sounds exactly like dating an old fashioned country girl from Texas but that's just me...just as scary...