Tex
You are gonna get a lot of answers on this but the best advice is to let her choose. A 38 special might be a good choice but maybe not. My daughter, who is 5 foot nothin', can handle a Glock 23, a full sized and compact 1911 and, an LCP. While she can shoot them all very well, she loves the LCP. Being that she likes it so much, and it small enough for her to carry anywhere, this is the gun I am giving to her when she gets her permit this summer. If she wants something else, like the S&W 637-2 that I just bought, she can have it.
Remember, small guns are for experts. I am not sure who said this but it is true in that they are generally harder to shoot accurately. Some of the difficulty can be alleviated by changing grip on small revolvers, etc. Most of the small guns from the LCP to the J-frames have lousy sights. Oddly enough, this can be alleviated by changing the grips as well, as long as you change them to Crimson Trace grips. Also remember that these are not target guns. Don't worry about whether she can put five into a quarter at 10 yards. If she can hit an 11x14 posterboard rapidly out to 10 yards she will be well armed.