There is no legal minimum age requirement for babysitting in California. However, babysitting courses start at age 12 and the guidelines for military families is also age 12. So, assuming that your son is responsible enough, he would appear to be more than old enough.Best of luck.f your nephew's parents are confident in your 15-year old son's ability and level of maturity, and you are, as well, then it should be fine. Babysitting age is a very individual thing. There is no legal minimum age. Some kids are ready to babysit at 12 or 13, and others not until 17 or 18.