They can’t accept criticism, blame or punishment.
Every child relives the classic story of the kid who says he didn’t eat the cookies while he has chocolate all over his face. First graders can’t admit wrongdoing, and taking any type of blame can result in tantrums. Because they’re insecure and boastful all at once, accepting criticism is extremely hard for them to do.
What you should do: Set reasonable rules and be consistent in enforcing them, but be very sensitive to this stage of your child’s life. Never tease or give unnecessary criticism. Think of discipline as a form of protection, not something to make your kid feel bad about herself.