4" K frame Model 15 or Model 10, preferably a good used Model 15. Whatever grips suit her and/or get one of the laser grips.
OR,
The 3" Model 60 .357, the one with the underlug and adjustable sights, and load it with 38's. If you can find one of the early ones chambered in .38 Special even better but they are kind of scarce. If they made a 4" J-frame I'd say get that but I don't know of any.
Obviously, let her handle both and make up her own mind.
Reason is mostly that either will have enough weight to dampen recoil a bit. Recoil of one of the flyweight scandium .38's is way too fast and snappy. Even that little model 60 can be sharp with full power loads.
We had a training class for women at our sportsman's club back in Payette. We had a few members' loaners for them to try and by a large majority the ladies liked either the K or J frame smiths.
Don't discount your mom. About a year after taking the class an "older" lady (I want to say about 80 but could have been in her 70's) who lived between Ontario and Vail, OR had a couple of guys try to come into her house in broad daylight, they were trying to force the locked front door. IIRC it had a small, high window in it and she fired one warning shot through that window over their heads causing them to run like hell. In the newspaper article she cited her training at our club for giving her enough confidence to use her gun when she needed to.
