Uh, at 14 she's hardly done growing. I didn't stop growing a lot until around ~18, and even after that I added an additional inch or so before I was 21.
VLC is ridiculous at any age, specifically that young. Expect her to struggle in all aspects of life on that diet at that age.
When I was a teenager I ate even more carbs than I do now probably, and I couldn't imagine how bad I'd feel restricting my diet at that age. If my mom tried to control what I ate, I'd rebel and just eat at a friends house and sneak junk food all over the place. Have her eat her fill of fruit, and other starches, it really doesn't matter at that age. No one should be dieting, your metabolism is at its peak anyway.
I'm trying to figure out if there is something I need to figure out and then figure that out before it's too late and all hope is lost.
The tighter the grip gets, the more sand pours out between the fingers.