Sleep paralysis occurs as a person is moving into or out of REM (rapid eye movement) sleep, the deepest part of sleep. During REM sleep, the body is largely disconnected from the brain, effectively leaving the body paralyzed.
England and a few other countries start formal education at age 4 or 5. That's harmful and misguided.
Education in Denmark is compulsory (Danish: undervisningspligt) for children below the age of 15 or 16, even though it is not compulsory to attend Folkeskole (public school). The school years up to the age of fifteen/sixteen are known as Folkeskole, since any education has to match the level offered there.