Yes you are late, but it's not too too late to rehash this argument.
I'm not saying Cal Poly SLO is not a good school, it's just generally looked upon as a mid-tier school that many students pick as a 2nd or 3rd backup (if at all). It's not generally known for interesting research, an active alumni network, or anything special in reality. I'm glad you got accepted there but keep in mind, it's not a very well known school even inside California.
I did make a mistake dividing by the total school population, instead of the class size, I didn't really look at the numbers carefully because my overall point wasn't to show that Uni High students don't get into good schools, but that the majority of acceptances are to mid to lower tier schools. When a school is so highly lauded, you really have to research where these students are actually accepted to, and when around 70% of the acceptances are to somewhat mid-tier to lower tier schools, it makes you wonder if the premium is worth it.