I think you'll be fine. Like tenting, you'll be living outside most of the time. Even if it is tight inside when it's raining, sometimes that can be half the fun. Playing board games or cards, or just sitting around talking and having fun.
This is just the beginning. After you have it a while you'll learn what you really want in a trailer. Like Jim said above, you'll eventually want something bigger. We went from tent to pop-up, to a 17ft hybrid, and now a 21 ft hybrid with a slide out.
What to look for: obvious signs of water damage, stained canvas, holes in canvas. Look for soft spots in the flooring. Open up all cabinets. The seats are cabinets too, so open those and check the flooring, especially the corners as much as you can get at. You can also check this from underneath. If any of the corners are rotted, the lift system can get bent up and twisted. This is repairable, but its a lot of work to take our the cabinets and seating to get at the floor.
Make sure they open it and close it in front of you so you can verify that the lift system is working smoothly.
Have them turn on everything, heat, AC if it's equipped, water pump, water heater if it has one, etc.
Look the tires and make sure they aren't cracked and/or dry rotted.
Be ready to walk away. There are lots of pop-ups around. If you have a mini-van with a tow package you can tow a 10 ft pop-up, so your options may not be as not limited as you think. We towed a '93 Jayco 1208 with a mini-van and it towed beautifully.
Most of all, have fun!
2013 Jayco Jayfeather X20 E, 2008 GMC Sierra 1500 Crew Cab Z71 SLE