When I first came to China, I taught English…and I sucked at it.
My students would ask me questions and I didn’t know how to answer. English just…is…for me. That’s how Chinese is for native speakers.
Native speakers are GREAT for conversation once your level is high enough, but they’re very rarely good teachers. Not to mention, their English is often not good enough to explain the nuances of the “problem initials” or “nasal finals.”