Kindergarten is no longer about milk, cookies and nap time, but enabling youngsters to master critical thinking at an early age to succeed later in life, supporters told Nevada lawmakers Monday during a hearing on mandating full-day kindergarten statewide.Supporters of Senate Bill 182 said under new common core state standards, kindergartners at the end of the year are expected to be able to write opinion essays and comprehend math."These are high standards," said Pat Skorkowsky, deputy superintendent of the Clark County School District.Sen. Debbie Smith, D-Sparks, said full-day kindergarten has been in Nevada law since 2005, but the Legislature has …