CA state law says a child must be 5 by Dec. 2nd to start kindergarten. If a child is born after Dec. 2nd, they can be admitted once they turn 5, at the discretion of the district. (But are supposed to agree to a full year of K the following year.)
My understanding is a school won't get ADA for a child that doesn't meet these criteria. Do you know of districts in CA that have early entrance? I would love to read up, and educate my district if there is a loophole.