If this is for both of you to shoot you have to take the size of her hand into consideration. Outside of a single stack magazine the auto' s will probably not fit her very well. The DA revolver I say is the best bet. I would recommend a 357 and let her get used to it shooting 38' s. Then let her move up the the magnum loads. For a defensive firearm, power is not the most important factor, training and the ability to hit your target is, if you can' t hit what your shooting at with a 38 or 9mm, the 357, 40 or 45 won' t do you a damn bit of good. Look for a used revolver to start and move up from there.