Because this bill is loosely based on the age limits in the U.K where it is five. Well, that's part of it; the other is that there has to be a lower limit somewhere and five seems like a reasonable number.
Mind you; what age do children start going to school in the States Atlasia?
Variously between ages 2 and 5. Some states mandate pre-K, all states mandate Kindergarten, so at the latest age 5 (and that would be starting Kindergarten later than the average student).
In New Jersey, public schools are required to offer pre-K to 3-year-olds, though attendance is not mandatory, and locally some public schools offer pre-K to 2-year-olds. I started school at age 2, but I began at a Presbyterian school. The law requiring public school systems to offer pre-K was passed when I was in middle school, IIRC. (My parents were heavily involved in lobbying for it.)
