The mandatory age children in Illinois must be in school is from seven to seventeen-years-old, but the starting age could be lowered in the near future.

WQAD in the Quad Cities reports Illinois Senate approved lowering the start age of 6 (which many parents follow) to 5-years-old. One Democrat supporting the bill said this:

It’s time for them not to wait until their 6-years-old to start school. If parents feel that their kids who turn 5 over the summer months, then they have the extra year to make sure their kids are ready.

There is opposition, though, from fellow lawmakers.

Parents are very concerned about the state taking the decision away from them. A lot of kids aren’t prepared to go to school at age 5. This makes that mandatory, it takes that [decision] away from parents. -  Peoria Republican Chuck Weaver

Additionally, all school districts in Illinois would be required to start kindergarten classes for five-year-old children.
