I advise against the airweight .38's. The cartridge is on the barely acceptable range for self-defense (YMMV! YMMV!), and the recoil is very stout, which when combined with the short sight radius makes accurate shooting difficult for the new shooter (YMMV! YMMV!).
If it's not going to be carried, for a revolver I would recommend a steel mid-size revolver in .38 with a 3-4" barrel.
Semiautos may take a little bit more education, but they're not that complicated, and let you use the 9mm, .40 cal., and .45 cal. (Which, subjectively to me, all recoil less than the .38 does in an airweight and still have more power). Glock 19, XD, or M&P are fine choices.
The advice chorus will tell you, though, to have her shoot a lot of guns and pick one she likes. They're right, too.