I am 19 and having a credit card since I was 16 was great. I think it is an excellent idea, as long as there are limits. I could only use it for gas, buying things for my parents, buying things approved by my parents(like cleats for soccer that they had agreed to pay for), and finally I could spend it if I ended up in a tight situation with out enough cash(but I had to pay my parents back that week). Its a good way to start with credit cards and allows someone to learn when to use them properly.