What level of music theory do you need to start composing

For example is just knowing keys, simple chord progressions, inversions, modulations and notations enough to start? At this level would probably be ABRSM grade 5 theory. Would that be enough? Or would deeper knowledge be required, like in grade 6 ABRSM theory you start to learn how to write chord progressions, avoid parallel fifths etc. I want to start now but still scared of starting without fundamentals and potentially going down the wrong route ending up having bad habits and such. Of course i do have knowledge of form and structures like baroque dance suites (Allemande, Courente…) sonatas, minuet and trio and some more.