Hey Buster
We bought my niece a MOSSBERG model 510 mini pump in 20guage (yes confusing model/guage) and introduced it to her when she was 11. She quickly earned the nickname "Whiplash" within the waterfowl crew at the time. It took 4-5 days of one on one hunting (in the blind) with just the two of us before she was comfortable toting, mounting and shooting safely. And then ----- watch out the girl was a dead shot! My niece used this shotgun for the next 5 years and has bagged just about every waterfowl available on the foreshore in the LML with it. This includes shooting the ONLY speckle belly our crew has EVER taken home for supper, came in with some Canada's during youth opening 2008/09 season. We upgraded her to a 26" Moss field pump (still 20G) for waterfowling but we cannot pry the mini out of her hands during grouse season. I must mention that my prior to my niece getting the mini pump 20G she was as well versed as a youth of 11 can be in all aspects of firearm safety and the safety concerns inside duck blind (especially with the dog present).With our observations of her skill level, safety awareness, physical build, and comfort level with firearms it wasthe right choice for us to start her with the 20G.
Hope this helps
Links
ps she still kills me a the trap meet with that newer pump, shoots 22's regularly
trying to convince her to try out and compete