Welcome to the forums and greetings from central Kentucky. Before I bought an AS trailer I researched my tow vehicle (TV) for its capacity, then followed the wife's marching order: "You can buy any trailer as long as it's an Airstream".
I was thinking about 17-19', she was thinking about 25-27'. We found a nice couple with a 23' not too far from our home and now she's ours. When it comes time to move up we're considering the 25-27' but we'll have to upgrade the TV, so nothing in the near future.
If you're handy around the home you'll be fine. It doesn't take more than that to do the day to day activities on the road. For the difficult tasks you can always go back to the Airstream factory (mother ship). They're not cheap but they're good.
If you don't have experience towing you should look into RV classes in your area. You can also rent various sized U-Hauls for a weekend to learn more. Airstream rallies are another good source of information.
So hang around here and read the various forums. I use the New Posts button to stay current but you can search for specific topics (use Google).