My suggestion (which went rather long winded and turned into general musings on the subject):
Get her comfortable with a full-sized 9 mm first. Once she can comfortably handle that (and that may be 5 minutes or 5 months), put a bunch of smaller guns on the bench and let her put a magazine or cylinder through each of them. Warn her that they aren't supposed to be comfortable guns - she won't LIKE them compared to the full size gun, and that's okay. Remind her that she is looking for a gun she can control and will consent to practice with, not a gun that is super comfortable to shoot.
We can give you some general direction, but especially with the little guns, the perceived recoil will vary wildly from person to person.
Listen to her feedback. If none of your existing guns is to her liking, come back and tell us what she said about the guns she did try. Then we might be able to point you in a good direction.
Backing up even farther...particularly with new shooters who want to carry, and even more so with women (who tend to feel the recoil more and have a harder time concealing) - I encourage them to get a first gun, then a first carry gun, and then worry about the perfect gun.
First gun: Something big enough to soak up the recoil, with proper sights. Generally, a full size 9 or beefy .357 (no snubbies!). Learn to shoot. Shooting it will be relatively pleasant and they can develop a level of accuracy with it that builds confidence. Such guns will do nicely as a "house gun" or can always be sold off to finance the first carry gun if necessary.
First carry gun: Criterion #1: Don't buy a POS. Criterion #2: Get a gun that is small enough that you will actually carry it. Asking most women to jump right into CC a Glock 26 or the like is a bad idea - with current women's fashions, this is GENERALLY going to mean an entirely new wardrobe. There are of course exceptions to this, but if she's wearing women's jeans and the relatively clingy and/or lightweight fabrics that most tops are made of, just where is the gun supposed to go? Her yoga pants will not accommodate a gun belt. If the gun is too big, it will stress her back, become a burden, and make CC such a miserable experience that she gives up. If her personal taste and career mean that her closet is full of cargo pants and unisex-type tshirts, then yay for her, she won't need to compromise nearly as much and learning to carry should be a lot easier. But that's not the majority of women I meet.
Start small. I find that something the size of an LCP or P32/P3AT is generally a reasonable size to conceal under "fashionable" women's clothing. She will have to make some compromises, but not so many that she is discouraged.
Is .32 or .380 a great defensive caliber? Hell no. But neither is .xx BIGBORE if it's sitting in your safe while you are in a parking lot with a mugger. Remember, if you KNEW there was going to be a fight, you'd stay home or bring a rifle. In the end, most handguns are not what you want when your life is on the line, but we carry handguns because walking around with slung rifles is impractical and socially gauche for most of us. It's better to have something than nothing.
Have her get used to carrying. If, once she is acclimated to carrying, she wants to step up in capacity or caliber, then she can go shopping and she'll have the shooting and carrying experience necessary to push the compromise in firepower versus practicality as far as she can.
thank Jesus S&W stopped making 'em, though...
