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.
Compulsory education laws require children to attend a public or state-accredited private school for a certain period of time. There are certain exceptions, most notably homeschooling, but virtually all states have mandates for when children must begin school and how old they must be before dropping out. Typically, children must start school by the age of six and remain enrolled until they are at least 16.