If the lady has arthritis in her fingers, then she may not be able to operate the trigger of a revolver or some double action semi-auto's.
It's important that she likes shooting it enough to become good with it. And no other round promotes fun and enjoyable practice like the .22LR.
There's so many different .22 pistols to choose from verses the .22 mag. that the .22LR might be the best way to go.
Find her what she likes and then teach her how to shoot it well.
Most .22's can be fired as fast as one can pull the trigger.
And proficiency helps to develop accuracy.
No one wants to spend a lot of money to buy .22 magnum ammo for practice which is quit pricey. Just stick with the .22LR and then let her shoot reliable hyper-velocity rounds for self-defense.
Meanwhile there's standard velocity type rounds for practice.
And if she ever needs to use it a .22LR pistol can be really loud when fired indoors, especially some of the hot .22LR rounds when fired from a short barrel.
I listened to a guy shoot some Aguila Maximum ammo from a Walther P22 short barrel and there was some seriously loud blasting. I would have hated to not have had any ear protection on. Plus they come in different pink patterns that appeal to many ladies. And they can also be easily outfitted with a laser sight on their accessory rail.