I'm not entirely sure about that. I have very small hands, but like most jazz guitarists, I have a strong preference for a relatively fat neck profile. A guitarist's fretting hand is effectively a class three lever, with the thumb as the fulcrum. If your technique is even remotely correct, a very thin neck gives you less mechanical advantage when fretting.

I think that the key beginner mistake is gripping the neck like a baseball bat, rather than simply using the neck as a place to rest your thumb. The wonderful Toone/Strandberg trapezoid neck profile suggests that the conventional wisdom on neck profile might be utterly wrong.

I do strongly advocate short scale lengths - most women and teenagers should at the very least lean towards a Gibson-scale instrument and may be better off with something in the 22" to 24" range. IME a lot of female guitarists gravitate towards using a capo on the 3rd to 5th fret, partly because it brings the guitar into a more appropriate register to accompany the female voice but primarily because it gives them a shorter effective scale length.