We must have gone to school in neighboring states or something, Alicia
I went to kindergarden, elementary school (grades 1-6), junior high school (7-9) and high school (10-12). Never even heard about middle schools until I was an adult. The school district we're in now has them, though, so I expect that my kids will do elementary school (K-5), middle school (6-8) & high school (9-12).
This is what you get when each school district can pick their own format
But it does give an author a nice amount of flexibility -- you can choose whichever might suit your plot best.
PJ
who grew up in Pennsylvania
