The sooner she learns the world isn't a free ride, the better. No employer, or even someone willing to take on a working student, is going to be impressed by the resume of a 14 year old if the attitude isn't there to back it up. Regardless of her experience, she's going to start on the bottom of the totem pole, mucking stalls and feeding horses like everyone does. Acting like you know it all at 14 is a big turn off to most people considering working students. It's simply the reality of the equine world.
I took on a position as a working student when I was 18. I've been around horses since I could walk, trained my own mare from birth, done Pony Club, competed in various events, trained problem horses and assisted in training of others. None of that mattered and I was grateful for the chance to scrape poop from the back sides of $50,000 horses. My attitude paid off and my responsibilities grew. It's amazing how little you realize you know when you admit it and open yourself to everything you can learn slaving in the bottom of the barrels.
Nobody is trying to be mean here, just realistic. If you want to make it in the horse world, those are facts that have to be faced!