Hate to burst your bubble about being "smarter than the teacher" but here's a quote from a study guide which debunks your theory about the gender of the narrator:
"The narrator's gender is not identified, but Poe probably intended him to be a man. Here is why: Poe generally wrote from a male perspective, often infusing part of himself into his main characters. Also, in major short stories in which he identifies the narrator by gender?stories such as "The Black Cat," "The Cask of Amontillado," and "The Fall of the House of Usher"?the narrator is male. Finally, the narrator of "A Tell-Tale Heart" exhibits male characteristics, including (1) A more pronounced tendency than females to commit violent acts. Statistics demonstrate overwhelmingly that murder is a male crime. (2) Physical strength that would be unusual in a female. The narrator drags the old man onto the floor and pulls the bed on top of him, then tears up floorboards and deposits the body between joists. (3) The narrator performs a man's chore by bringing four chairs into the old man's bedroom, one for the narrator and three for the policemen. If the narrator were a woman, the policemen probably would have fetched the chairs. But they did not."
*does a victory dance for teachers everywhere*
Also, all you kids got to remember that nobody is perfect, and teaching is a thankless job. Just because you're a teacher does not make you all knowing or infallible.