1. Teaching will be a breeze.
You’re thinking, “I already speak English so this’ll be a piece of cake!”(Good idiom to use in class by the way). In reality, speaking English is in a whole different universe to teaching English. Most native English speakers never learned grammar rules the way ESL students do. Can you explain the difference between “which” versus “that” or when to use “I will” versus “I’m going to?” You’ll find yourself learning a lot more of your own language than you ever did when you were in school.
Also, for Americans out there, most schools around the world learn British English, so you’ll need to speak in a posh accent, use “lift’ instead of “elevator,” and learn to tweak your spelling. (Just kidding about the accent).