I have a Kel-Tec PF9 which is what the Ruger LC9 is formed after. I gonna be honest, this is the most painful shooting gun I have. It's small size seems like it would be easy to handle but it is like a tazmanian DEVIL when you pull the trigger. I would advise you go somewhere and let your wife shoot it before you buy it. My wife shot it once and will not touch it again.
Go get her a Glock 26. That is what my wife has and LOVES it.