Looking into it more, I found this:
http://articles.sfgate.com/2010-09-30/news/24106416_1_governor-signs-bill-kindergarten-cutoff-dateThousands of 4-year-olds will be held back from entering California's kindergartens under a bill approved by Gov. Arnold Schwarzenegger.
The law he signed Thursday moves up the cutoff date by one month each year for three years, from the current Dec. 2 deadline to Sept. 1. California has one of the latest start dates in the nation.
The Legislative Analyst's Office estimates the state could save $700 million per year by reducing enrollment. Under the law, half the savings will help plug the state's deficit.
