Question:
What about those who are taking a class that most of your grade isn't? I mean like one of those classes that will be filled with people in older grades.

My Answer:
I will try to give my best advice but that has never happened to me. Try not to make a big deal out of it, it's better to keep it low and act like its normal. And if it's a class higher or lower just treat it like a normal thing. And if it's a higher class then that means it's great, that you are taking a class above your normal class. If that's makes sense.