If you have found a floorplan you like other than the 40' length, I would go with it. Really, a 34' class A is not terribly different from a backing/parking/setup perspective than a 40' class A. She will have all the same challenges to overcome, and in the end it'll be a breeze for her to handle.
I made the same mistake buying a horse trailer. My wife was to be the primary user, and would be pulling it 90% of the time. I wanted a 4 horse one that was 6' longer, she was worried that it was too big. We ended up buying the shorter 3-horse one. At least once a month after that, I had to hear her complain that the trailer was too small to do what she wanted to do.
We finally sold that one and ended up with a 4-horse one with a 10' living quarters that was 20' longer than the original. She pulls it everywhere with no problems.
Moral of the story: Driving an RV is driving an RV. Driving a 32' class A presents the same challenges to a new driver that driving a 40' class A does. They are all intimidating at first, and become second nature in the end. Don't sacrifice features for fear. The features are tangible, the fear is not. After you overcome the fear, the lack of features will always make you regret your decision.
2002 National Dolphin LX 6356
Workhorse W-22 chassis
Don't believe everything you think.