As I'm sure everybody knows, you can't "make" her like guns and shooting. Since it certainly seems to me like the Mrs. has a good attitude, possibly you could stress to her that part of the responsibility of firearms ownership is proficiency, in addition to safety. If she appreciates the availability of a firearm for self-defense, she should appreciate the need for periodic live-fire practice just to keep up her skill level.
This is the approach I took with my wife. Her passing interest in shooting has slowly increased to the point where on occasion she will ask me to take her shooting, and appreciates the need to maintain a baseline level of proficiency.
I can only hope that by her getting more live fire experience, and by trying to make each shooting experience as enjoyable as possible for her, she will want to do more. So far, so good. But it has been a long, slow process.