Is 15 too young to get a part-time job?

My oldest daughter will be 15 very soon. She has been talking about wanting to get a job. Here in GA, a child can have a job at 15 with a work permit from the school superintendent. I would like for her to have the chance to see what it feels like to earn her own money but I don't want her to take on too much too soon. She's a freshman in high school and her grades are okay. Should I allow her to get a job or tell her to wait another year or 2? If she does get a job, how many hours a week is enough? I'm thinking enough to make $50 or $60 a week is good enough. It's not like she has bills to pay. This money will be for her personal enjoyment only, clothes, shoes, makeup, cell phone minutes, jewelry, cds, etc. (all that teen stuff).