Just be yourself, Happy. Be yourself.
The true you will show through even your nervousness. Don't expect to remember every little thing you'r shown tomorrow, the next day, or even the next few weeks ! Make mental notes, even litte written notes to yourself IF you get a minute or two somewhere in the day.. if not, do this when you get home, then organize your little memos during the week at home.
Be HONEST about what you know, don't know, and WANT to know. Show genuine interest (as I know you will) when learning something new.
You'll be GREAT !!! And keep that beautiful smile, no matter what !