I have a .410 because my Dad passed it along to me.
I wouldn't have bought one myself (well, probably not - ok, maybe would have just to say I have one and to fill the hole since I have a 28, 20, and a 12 as well).
I find you need to be a decent shot with the .410 compared to a 20 gauge, which is my favourite shotgun gauge (and I'm 6'1"/200 lbs, so not "afraid" of a 12, just don't need it for upland birds/bunnies).
The .410 needs to be aimed, where the 20 gives you some room to be "off a little" and still take out the target.
But for anyone that is very recoil sensitive, the .410 would be a "viable" shotgun. There isn't the greatest variety of them out there, at least in "starter" price points. The 500 Mossberg pump's fit/finish is half decent and may be the best "lower cost" .410 option, although it has the "standard" (14") length of pull. There is a Mossberg 510 "mini pump" for about 50 bucks more than the regular 500. It has inserts to make the LOP 10.5 to 11.5" but only has an 18.5" barrel, but depending on what she would use the shotgun for (shooting vs hunting), it could be viable.
If you want to spend some bucks, Browning has a fine .410 (Micro Midas) for smaller framed shooters