That's pretty bad xD But things like that happen. Also, it wasn't entirely your fault, so there's that at least. My advice? Be a little embarrassed! Feel kinda bad! That's how you learn, and ultimately it will make you a better person c:
I'm surprised that a transfer student wouldn't know the term "culture shock". Usually, before a student goes to study in another country, someone (a teacher, parent, someone in charge of the exchange program) will inform them of it. No matter where they're from, or where they're going, culture shock is almost always a big adjustment, and it's typical that they are informed of it before leaving (or soon after arriving, at latest).
As long as he said that everything's okay between you two, you're fine. One embarrassing mistake isn't so bad.
not all of them seem to do that, actually. i lived with a couple of korean girls several years ago, and it was a learning experience for everybody. they didn't understand that the house owner wanted rent every month, not at the beginning of the term. nor did they understand other things that were pretty common to our area (tho i thought that the guide counselor at their school would help them with that, but for some weird reason she didn't teach them as much as i thought).