My two cents- the Mossberg 500 tactical, for 2 reasons: 1) pistol grip and shorter barrel. The pistol grip changes the way you shoot, i.e. not having to have it up at your shoulder. Cuts down on that big kick/recoil that a smaller person may find objectionable. But the biggest reason is because you stated that you are using the gun for home defense- if a bad guy is in a room and you are coming down the hallway, the last thing you want her to be leading with is an extra 18 inches of barrel and stock. The bad guy reaches out, grabs the barrel and now is in control of the firearm. The 500 tactical is shorter and can be fired from the hip. 2) The stopping power of a 12 gauge is better than a 20. If your life depends on it, you want something that will drop the bad guy, not injure them but let them stay in the fight. Again, my two cents.
