Welcome to the forum. Feeling excited, nervous and overwhelmed are pretty much normal emotions for any major purchase, especially a new RV.
There is an excellent Pre Delivery Inspection checklist on the forum. You can access it here: http://www.keystonerv.org/forums/showthread.php?t=5129
Check it out, download it, take it with you when you go to pick up your new RV. Using it will help you identify anything that might need repair/adjustment before you take it off the dealer's lot. It's much easier to get things repaired while you're there (before the final signature) than it is to haul it back a week later with a list of "need to fix" things.
Enjoy your new trailer and again, welcome.