I started too with vocabulary, but grammar for sentence creation is a problem. The logic for word formation and expressions are so complex. German is one of the type of languages where you need logical stimulus with emotions in sentences.
And that thing where most German words have a couple of different meanings... God damn, it's like I'm re-learning Russian, which has the same stuff going on with different type of logic.
English is as easy as candy from a girl.
Never liked DuoLingo 👍🏻