The rest if your point is simply wrong. Focusing is a physical activity that you can train for. Every good chess player that plays classical trains for that. And so do (or rather so did) students in the education system. Taking mock tests before the finals is a way to train your endurance such that you will be better able to keep your focus throughout the test.
There is nothing wrong with me.
Maybe asking teachers is better. Maybe a robust metric across generations and across population simply does not exist, and cannot exist, and we just have to accept that we cannot compare the education of kids in America today with the education of kids in Guatemala a decade ago.