Colleagues were congratulating Walter Hays kindergarten teacher Diana Argenti Friday morning as she prepared her classroom for the arrival of students. Argenti and Natalie Bivas, a Palo Verde School reading specialist, were behind a bill signed by Gov. Arnold Schwarzenegger late Thursday mandating that California children be 5 years old by Sept. 1 of the year they start kindergarten. Photo by Chris Kenrick/Palo Alto Online.