A lot of good advice here already so if you’re set on a .22LR then there’s not much to add.
But if I can interject with just something else to consider, take a look at the Glock 42 in .380. It’s tiny, easy to manipulate, and uncomplicated. With a bit of practice she could be shooting it as well as any .22LR and have a much better defensive weapon at her disposal.
Having said that, the best gun to have when you really need one is the one you have with you at the time. So good luck with whatever you choose...
