I liked it so much when I rented it back in May '12, that I immediately bought one and have never regretted buying it.
As mentioned, the Shield is very tight to operated and manipulate, so do make sure she can manipulate the slide.
Also... If at all possible, she needs to rent one, or try someone's, to ensure SHE likes shooting
it. Many subcompacts feel good when fondling it at the counter, only to NOT like how it feels to shoot. Not so much with the Shield, but still... If she doesn't like shooting it, she won't want to practice with it and subsequently, won't carry it.
As mentioned (also), the mag springs are VERY tight and getting that last round into the mag, when new, is near impossible. If you don't already own one, if/when you get the Shield, also buy an UpLula (Universal Pistol maglula). You won't regret it.