If she has shot your .40 and didn't complain too much, a 9mm would be a piece of cake for her. I personally would not let my wife rely on a .22 as a carry weapon. Is a .22 better than nothing? Maybe. It is absolutely not better than the bad guys 9. Why screw around? Common opinion is .380 is minimally acceptable. Anything less is a gamble not worth taking. Good luck.