What does she want it for? Just to shoot or to carry? I would suggest a browning buckmark .22. Much more fun to shoot and it would be cheaper, and maybe more accurate as well. My ex wife loved hers. I had a browning Hi Power as well. They are a bit thick if you have small hands (I do), rubber grips helped a little. Sub sonic 9mm round will have less recoil than a .40 SW as well.

Or you could get her a .357 and shoot .38's out of it to train her. Then if she wanted full power she could shoot the .357 rounds. I don't have any trouble with .357 rounds in a full sized revolver and I'm pretty little.

The 380's are nice as well. I had a PPK for a while and it was a nice little gun.

Find a place that rents them and let her shoot a few to see what she likes.

Paul