Good advice, that.
I recommend a 20 gauge for most women and even some men; it’s about 75% as potent as a 12 gauge, which should be more than enough to drop almost all perps, and the recoil is much more manageable. Get a youth model with a smaller stock, shorter barrel, and you’ll have yourself a dandy home defense gun. As for shot size, I don’t know if it matters all that much; I prefer 00 but I know some folks have penetration concerns.