But Glendale school board President Greg Krikorian said the bill is another attempt by state legislators to nickel-and-dime school districts.
"Manipulating and playing with the start date for children in kindergarten only gives these legislators an easy way out," he said. "The whole thing is ridiculous."
Simitian's office estimates the change would save $700 million annually. Half the money would help fund a state preschool program, and the other half would pay down the state budget deficit, which is now $18.6 billion, according to state Controller John Chiang.
About 100,000 California public school children are estimated to have birthdays between Sept. 1 and Dec. 2, but Glendale Unified officials were unable to immediately determine how many of its 1,715 kindergartners would be affected.
The bill's advocates and some child psychologists say beginning kindergarten later may lead to more positive student growth.
"Teachers tell me, 'We can tell in third grade which kids started too young by virtue of their performance in the classroom,'" Simitian said.
About 25% of California's K-12 students start school before turning 5, he said.
"I can't imagine any system where we'd say let's put 25% of kids in the system at an age where they are more likely to struggle than not," he said.
The bill's intent is not new, school board Vice President Joylene Wagner said. But the Five Star Coalition, where Glendale Unified joins school boards of La Cañada Flintridge, Burbank, Pasadena and South Pasadena, has yet to endorse the measure. A formal endorsement requires approval by each school board, but the coalition has been elevating the bill's impact to finances and local control in its state and federal legislation agendas, Wagner said.
The California School Board Assn., of which Wagner is a delegate and board member Mary Boger is vice president, supports a September kindergarten start, Wagner said.
"There have been bills, I think, before that haven't gone through, and now it may be with the added budget impetus, that anything to save money gets an extra look," she said.
Glendale Unified may have kindergarten classes with 30 students on average next year, up from 20, since board members voted for bigger class sizes to help close a projected multimillion-dollar budget deficit.
Kindergarten has become more academically strenuous than it was when classes were 30 students on average in the 1990s, teachers said. There were fewer academic assessments and more instructional aides.
Students learning English take a state language development exam, but all kindergartners take a series of district benchmark exams throughout the year.