An A on the test is nice. Understanding it well enough to teach it is what follows you.

A grade records that you could produce the right answers on one particular morning. Explaining it to somebody else takes a sturdier kind of knowing, because you have to understand why the method works and where a person tends to go wrong. That is the version still sitting there in two years when the test itself is gone. Grades expire and comprehension does not.

After the next exam, try teaching one topic to somebody in your class who is behind on it. The holes in your own understanding will show up inside five minutes. Filling those is worth more to you than the points were.