1-Join your local gun club
2-take NRA Basic pistol-borrow pistol
3-take NRA personal protection course-borrowed pistol
buy gun
if you don't do this previous suggestion go to a commercial range and take a few lessons renting various guns and find one you and your wife can feel comfortable running well-then buy the one you like and can afford budgeting two times the guns cost for ammo and training.
And remember a pistol is what you use to fight your way back to your carbine