Congratulations! You're gonna' love it ... and it looks like a reasonable price, so you got a bit of a deal to boot.
Now, just stick around the Forums and we'll give you more advice, such as what tools you HAVE to have with you at all times, where you MUST go to camp, what mods and hitch are just totally NECESSARY for any Airstream, etc.!
But you know, every so often, I wish I has those extra two feet that you just got, or wish I had the bedroom up front, or wish my trailer was actually seventy feet long, etc. Then I just shake my head, hitch up, and go somewhere. And almost everywhere, I'm happy with what I'm towing and that it's not the backpacking tent I used to always use!
Enjoy!