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Jazz theory is super fun to learn and it can be applied to any genre or area of music. I've been studying it for around 2 years now and still have huge gaps in my knowledge. 

If you plan on writing more jazz in the future, I would reccomend listening to some classic records and paying attention to what each instrument is doing. Just like any genre, that is the best way to learn how to write it. Listening. The classic Miles Davis quote is "You have to know the rules before you break them" and that is very true too.