It could easily have been "the height of education" even a hundred years ago. After all, a hundred years ago antibiotics had not been invented, and no one knew about quarks or even electron shells. No one knew about DNA; Mendel had just been rediscovered. High school students today know things that no one would have known then, simply because the fields they're being taught about have progressed.

On the other hand, modern high schools teach almost nothing about theology at all, so a medieval cleric would be horrified at your idea of ideal education. You aren't taught what counts as a sin or how to atone for one, and you haven't been taught about the fundamental nature of God, have you? Your calligraphy is probably crap. You don't know how to plow a field, when to plant, or when to harvest. You can't make a sword, and you have no clue how to use one beyond "pointy bit goes that way". And I bet you can't even make your own clothes. Do you know Latin? No? Well, you might barely even qualify as literate; writing a language people actually speak doesn't count. Really, American education is useless in every possible way, if you live in medieval Europe. It's remarkable that we can spend so much time teaching our children without them learning anything important.

In other words, answering your question is going to be difficult. Education is not a static thing.