I think a lot of people choose small gauge guns that are the wrong ones, and for the wrong reasons.
It's a much more complicated topic than people understand and running off to Cabelas isn't going to solve the problem for most people.
First, I'll tell you my solution having trained a number of youth wingshooters. I start little kids with 12 gauges. Always a break action, usually a SxS but occasionally an O/U. It doesn't matter. It's not the size of the bore that is the problem, its the PAYLOAD OF THE SHELL. There is zero reason you cannot use a 2.5" subsonic 1050fps 12 gauge shell in a 3" chambered 12 bore shotgun. Recoil aversion isn't about the gauge, its about the recoil impulse. I remember teaching my six year old this way and of course on Turkey hunt day, I slipped in a more powerful load which she of course did not notice in the heat of the moment, and the success.
Next thing to remember is 99% of sub-gauge shotguns available in America suck really, really bad. In the modern era of mass manufacturing and the desire to reduce parts, most companies only make two shotgun actions: 12 gauge and 20 gauge. If you buy the 16 gauge, its a heavy turd on a 12 gauge action. If you buy the .410 or 28 gauge, its a disgusting, unusable, overweight beast built on a 20 gauge action which then requires insanely heavy barrels to be big enough to mate up to the frame. You're not doing yourself or anyone else a favor by purchasing one of these. It's just a punishment of low quality, high price, and carrying an overweight, unpleasant gun needlessly.
The third thing to remember is women are ruined for shooting by being handed a man's gun. Women have necks, men do not. Their drop at comb and heel requirements are much different, so they usually cannot hit the broadside of a barn with a man's gun and that's instant frustration. Women also don't want to appear weak, so they endure pain and smile, only to never touch a shotgun again. A woman's shotgun is cast at the toe of the stock, bending it away from their breasts so they aren't punching themselves in the bust during recoil. Men do not appreciate this whatsoever and I assure you, women do not like getting punched in the ta-tas.
The problem then lies in finding a properly weighted and balanced smallbore that A.) Weighs the right amount, B.) That balances, C.) that can be shaved down for correct drops at heel and comb, and D.) Can be cast (bent) to accommodate the shooter)
There are two guns I'm aware of for under $3000 that can accomplish these goals 1.) A vintage Orvis Uplander Beretta in 20 gauge with a Straight English grip. They weight 6lbs, can be cast, can be shaped, and they are balanced. 2.) The Dickinson's Arms (Turkish) SxS in 28 gauge is built on a true 28 gauge frame and are less than $2000. These two guns can be manipulated correctly and are low-recoil.