Agree with the gun probably not a good fit, Getting to a good stock maker and getting her fit for a proper stock could cost some sheckles but it would fit her perfectly. On the other hand $700 would get you a Remington 1187 semi auto Sportsman compact youth gun in 20 gauge with a mod choke and 21" barrel. Maybe not as good for upland bird hunting or busting ducks but it would be good for the home defense scenario and a great small game getter. Semi-auto's are just easier on the shooter.
I use a similar gun for HD, turkey hunting and a back up deer gun. Mine has hi viz rifle sights on it which makes it perfect for me for those uses but you could also mount a scope mount on it easily for minimal cost and put a low power scope on it. I use a 2.5X20 on my other gun and it works like a champ. Slugs or birdshot I shoot to point of aim with one setting on my scope and the same holds true for the gun with the rifle sights.
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