Giuliana Tapia was way behind her classmates.
She was just 5 years old, starting kindergarten at Telesis Academy of Science and Math in West Covina.
At a kindergarten screening two months before her first day, she happily chattered about her dog Toodles, her favorite color pink, her Santa Claus pajamas, her nickname Gigi, her outings with dad to see SpongeBob SquarePants movies.
But many of her 21 classmates already knew most of the alphabet, colors and shapes. Two of them could even read all 100 words — at, the, there, like — that kindergartners are expected to know by the end of the year.
About half had been to preschool; Giuliana had not.
“I don’t know,” she said when she was asked to identify letters on a sheet of paper. 
Then, anxiously, “But that’s OK, right?”
Giuliana is not atypical of Latino children, who have the lowest rates of preschool attendance among all racial and ethnic groups. A 2015 UC Berkeley study of 4,550 children nationwide found …