Congratulations on being an ambitious young person!  So there are no legal requirements for becoming a babysitter in the state of California, and really no age requirements as well.  What can make you a more marketable babysitter - and more confident - is taking some CPR and First Aid courses.  I will give you a link to the Red Cross, who offers those type classes in California.  As for setiing your fee, the more certifications you have the more you can charge.  Ask around to friends and family friends as to what they charge or what they are charged.  Good luck1