I suggest any 4-6 inch steel Ruger or Smith revolver in .357 would do her just fine as you noted. You have the choice to shoot .38 and .38 + p rounds or .357. It would last her a lifetime and the ammo would be readily available and somewhat cost effective. They can be found second hand as well, at more affordable prices as you already know.
"There is no hunting like the hunting of man, and those who have hunted armed men long enough and liked it, never care for anything else thereafter." - Hemingway
“The greatest ignorance is to reject something you know nothing about.”