Just as important as how to shoot, is WHEN to shoot. Everybody is all upset about shootings of persons that don't seem reasonable solutions to the conflict, or perceived danger.
Even the most trained shooters will be grilled in court on the Use Of Deadly Force. People have gotten so outraged at the unjustified UODF, that they now protest at the use of justified deadly force, before they know all the facts, or they just don't care about any facts other than one of "them" got shot. All kinds of people get shot.
In UODF, the standard that police are held to is you cant justify UODF just because you're scared. A law enforcement professional who is trained in defensive tactics and use of less-lethal force techniques, are expected to match the threat on the same level, and just a little higher, without going over. He will be grilled in a court over his UOF, even if he is granted qualified immunity. A CHL holder isn't held to the same standards because they aren't required to have the training, they don't have a dangerous occupation with qualified immunity, can still be grilled in court over their actions and possibly loose the case, like the case in Florida where Michael Drejka shot Markeis McGlockton. Every second of that conflict was scrutinized.
If you can, try to find a CHL instructor that doesn't have any hero or victim agendas. People make bad shoots being the hero and thinking they're the victim.
The best thing, AVOID a conflict. If you're living in a high crime area, move away. If you need gas and see bums hanging around, find another gas station.
For her, I would say at least have a 20ga shotgun for the home because it doesn't matter where you live now, you can get invaded,
But .22? naw. Need stopping power. But the boolit size argument can go on all day.
AND women will surprise you what they can do with a gun!