This is a question we receive frequently.

I have a 3-year-old; aren't they considered preschool? In Texas, children who turn 3 before September 1st are classified under Pre-Kindergarten 3 (PK3).

What do they learn? Similar to what four-olds learn. Here are the Texas Guidelines from the Texas Education Agency and Texas Guidelines Alignment from Region 13 that outlines in detail the learning outcomes between the two.