I would go to the NRA site myself and printout gun safety and handling rules and go over them with her line by line, make her initial each rule or page so she will take it more serious. Demonstrate with a blue, or toy, gun over and over. Go over finger placement muzzle direction, knowing what's behind your target etc. Treat all guns as if they are loaded all the time.
The second class go over the rules a second time, including the use of eye and ear protection. I would bring out the weapon in a controlled environment, perhaps a very slow day at the range to keep distractions down; or on some private property if available. Then let her get used to holding and handling the unloaded weapon exactly how she did the blue gun. Next, you load and fire one round off the target into the berm or back wall so she can hear the noise and see exactly what happens when the trigger is pulled. If you are able, set up a small sheet of plywood, or a cinder block for her to shoot. In my experience when people see the force and destruction the bullet can cause to a material object instead of a little hole in a piece of paper, they realize the power and responsibility for safety they now hold. Go slow and methodical always emphasizing safety.
Just my .02.