My choice would be one of the following and any of these would be a good choice: [1] S&W Model 17 (6"), [2] S&W Model 18 (4"), S&W Model 617 (4" or 6", I like the 4"), [4] Colt Trooper Mark III 6", [5] Colt Officers Model Match (6"), or [6] Colt Diamondback (4" or 6"). I would not choose anything made by Taurus, High Standard, H&R, Charter Arms, or Rossi if you are expecting a premium revolver. They all shoot, but they are not premium guns nor were they intended to be premium guns. You'll pay for any of these preferred choices, but you'll get over it when she is very happy plinking targets.
In a single action, I would choose a Colt New Frontier (6") with both 22LR and 22WMR cylinders, or Ruger Single Six.