The Marksman has a nice selection of guns to rent. You can try any of their rental guns all day long for $10. You can change as often as you like. If you go on a Wednesday the rental is free.
Two things to know though:
When you first go there, they put you through a safety orientation which is $10. (Good idea IMHO)
Also you have to buy their ammo for the rental guns.
Before I bought my pistol in 9mm. I tried out every 9mm they had in the case, which is several. Then bought the one that I shot best. I would recommend you do the same for your Mom.
The gun I "liked" because of looks and the one I shot the best were different guns.