My son, Robert, started kindergarten in 2004. He had a partial diagnosis at the time of developmental delay, maybe autism. I had told people in the school district offices that we wanted to put my son into school, but that he belonged in pre-K, not kindergarten. Unfortunately, the state rules said that pre-K was only for 4 yr olds, but the school district agreed to evaluate him. Robert was on good behavior when they tested him. Even though he was only speaking on a 3 yr old level and wasn't even good at saying the answers (they let him point), they decided he was fine. Just delayed with his speech. "He can go to regular kindergarten," they said. They should have been around to see him panic and throw a fit as we were leaving, because he was afraid to go down 5 stairs. Which resulted in me having to carry him down the 5 stairs, while he yelled his head off. But of course, they didn't see that. They only saw him during his 30 minutes of great behavior.
Robert's first grade teacher once said, "He's like that poem. 'When she was good, she was very, very good; and when she was bad, she was horrid." I'm not saying Robert is a bad child. He's definitely not. But he's a lot like Dr. Jekyll/Mr. Hyde. One day or morning, angelically sweet, kind, helpful, and smart. The next day or afternoon of the same day, yelling, hysterical, or throwing a tantrum, and refusing to do the simplest things.
But that's life with autism.