My brain is mush

My school has taught me well, But is it enough? The mitochondria is the powerhouse of the cell, I learned in biology amongst other stuff. And in history I am quite the scholar Because I know, in 1492, that Columbus sailed the ocean blue, to go farther I mean come on, it's history, nothing's new In English I am the best Trust me on this, I know Shakespeare At least enough to pass the test the rest bores me to tears And math is a piece of cake two plus two is fish. No work needed, I know their is no mistake I'm a whiz at this junk, no need to despair Now we have reached the end, and I hope you get the joke I am not stupid My brain is simply mush