Hiring a new employee is an investment on the part of the salon. It takes time and money to train a new hire. Stylist retention is important to owners. Losing stylists means losing clients. In a way, this question is asking "Are you worth the investment?"

That being said, ambition is a virtue.

And again, the only wrong answer is "I don't know."

Tell her how you see your professional life growth, not personal. She doesn't want to hear how you are going to be married with a new house and 2 kids, one boy, one girl.