Yeah i think you found the boss on accident if that's the quest name you were seeing.
But so did I, so this can't be that uncommon. I question the design of having some mid-game content in the same (surface) place as the end-game because it becomes unclear what you're being pointed at. Put simply, tell me to walk towards the giant chasm; I'm jumping in.
I realized I wasn't supposed to be there yet when I recognized a typical pre-boss pattern that Zelda games use a lot. Trying to avoid spoilers there.