“Mir geht es sehr gut.” is normal everyday German though. I’m not sure if it’s 100% grammatically sound but that’s the way people talk in Germany all the time. It might also depend on dialect, but I wouldn’t call that wrong, both examples work just fine.
I am just doing some “forum housekeeping” and due to the new split of Decks community courses and official memrise courses, there are now separate forums for Decks and memrise courses.