Isn't this statement still true in your example? (Assuming some small variance among the small schools just so it's still possible to order them by size.)
If one school has 1,000,000 students and a million schools had about 9 to 11 students, the median school would have about 10 students. No matter what (ignoring exact ties), 500,000 schools are going have more students than the median school, even if most of those schools just have 10 or 11 students. Sure, most people in your example come from the ~10 person schools, but more students come from the more populated half of those ~10 person schools. There's at least a 54% chance that you "attended a school with more pupils than most other schools" (6 of 11 million students).
(It's fair to ignore exact ties because it's unlikely that many planets have the exact same population.)
Your distribution makes it likely that there is one school with a much larger population than your own, but not that most schools have a larger population.