first, she'll need to get over that problem with the loudness. almost all guns i know of go BOOM! really loud when fired.
kick, on the otherhand, can be controlled a little bit better.
the Glock 26 (subcompact) is fine for both stopping power and relatively low recoil. depending on her hand size, the next up (19) might be better as it will help lessen recoil.
if she wants a revolver, make sure it's steel and not the light weight alloys. hammerless is fine if and only if she's strong enough for the double action. personally, i like having the option of SA or DA. and i just keep mine holstered so that the hammer can't be pulled back accidentally.
as far as revolver caliber, most women don't like the .357 at all. especially the shorter the barrel gets. and to be any good at it, she'd have to practice, practice, practice with .357. if she doesn't like to practice with what she'll shoot defensively, don't get her that caliber. (i know from experience on this one!) plinking with .38 is fine, but it's no substitute for the .357 practice. she has to shoot what she'll carry!!!!!