I'll echo the notion that ANY firearm purchase intended for a female be accompanied by extensive "fitting" - if they're not comfortable with it, they're not going to use (nor will they enjoy) it. What YOU decide best for her isn't necessarily what SHE will agree is best for her.

Let her try some on. Length of Pull is particularly important for obvious reasons. After shooting both for awhle, my wife isn't convinced that a 20 gauge Nova Youth I started her with recoils any less than the used, cut-down 12 gauge Remington 1100 she found on her own at the trap club. And, she shoots the 12 much better than she did the 20. Confidence is valuable.

I've noticed quite a few dedicated turkey guns sporting the collapsible, M4-style stocks as standard . I know these stocks are also available aftermarket (Knoxx?) for the Remington 870. I'd be tempted to have her try something like that as well. You may be able to get her into a 12 gauge 870 Express with an adjustable stock for not much more than you'd get into a 20 Nova Youth for? I own both the Nova and the 870. The Express is rougher than the Wingmaster, but is still more reliable than the Nova has been. The Nova will make a trip to the 'smith at some point here to correct the problem it has (and many others apparently have as well - google it) with light primer strike misfires.