"but I think it's a shame that most of the 15yr old folkie girls want to sound just like her"

We-e-e-ll, we all have to start somewhere, and most of us start/started by imitating our idols to a greater or lesser degree - I certainly did. 15 is a very young age for anyone to have a style of their own completely developed, but by getting out there and doing it, albeit in someone else's style, doors open and confidence grows.

I could think of a very great many, far worse singers' styles for a young lady to use as a crutch in her journey through music. And at least she sings with an English accent, and she sounds way better than Beyonce. :-)