From 3rd grade thru 12th, I went to the laboratory school that was connected to the university where my father was on faculty.
We had student teachers every semister. We only had 35 in each class. Our school building was right on campus with all 12 grades in 1 4 story building.
My senior class was the largest ever graduated, 50+. That's because the year I was in 8th grade, it was announced that
that year's 9th grade class would be the last to graduate and oh by the way, 8th graders if you want to go to summer school, we'll let you graduate with them. So, I went to summer school and graduated high school at 16.
