After spending a week on the range in my academy with a young lady who was 5ft nothin, and 100lbs soaking wet for a range partner I can say a 12 gauge is not the weapon for those of smaller stature. For my ex and my wife I went with a 20ga, when loaded with buck shot it has 3/4 of the stopping power of a 12, with 2/3 the kick. Much more manageable for smaller people. Pump in 20 gauge with a 20 inch barrel, folding stock, pistol grip, pressure switched light in the pump, plunger removed from magazine tube and bingo! Home defense weapon anyone can use.
Edit: and yeah, I spent a good amount of time on the range with them both after I bought it for em, heck my wife even combat reloads.