For some reason many people think a short barrel revolver like the J frame is a good choice for a new shooter, it is not. The short sight radius added to the heavier trigger makes shooting a J frame well difficult. It's more of a professional gun that a starter. This doesn't mean it's a bad choice, only that the shooter has to be informed that a lot of practice is necessary to shoot it well.
My suggestion, try and find a handgun SD class locally that provides the guns. This way she can use several types of handguns under supervision and decide which is best for her.
ArchAngelCD illustrated my sentiments exactly. Start a new shooter off with a full sized gun like a 4" L frame or a full sized 9mm auto loader, not a short barreled, small framed gun.
Small guns are harder to shoot accurately, the recoil impulse is stronger, and for a woman with arthritis will likely be painful. Starting her out with a 5 shot 38 special, even with light loads, could make things unpleasant for her.
Small carry guns should be introduced after shooting a full sized gun so they see the stark difference, and know fully what they are getting into.
I took my girlfriend shooting not long ago, and she stated she had shot a Kimber before and really liked it. I didn't have a 1911 along that day, but did have her shoot my HK45. She really liked it. She made a statement that she wanted to get a small little 45 to carry. I said "That's what I carry, but before you make that decision, I think you should shoot my carry gun to see how it feels." I had her shoot my XDs 45 and after one magazine she handed it back and said "I don't like it. It hurts."
If I'd started her on that gun, she likely never even would have considered carrying. She has since settled on a 9mm for carry. 38 specials don't kick much, but in a small gun, they may be more than she is ready for.