I would definitely encourage it but start small. She can start selling to family relatives than learn more about the business on the go. The key to this is start small and work from there like a lemonade stand. I wouldn't advise to wait because the interest may be gone and you'd lose valuable time and impetus. Starting small will help to balance school work and learn on the go. It'll help offset too any huge potential loses. For example start with a hand held mixer which can easily be purchased for $50 rather than a cake mixer etc., good luck!