I would say the theory is so important to learn it ASAP. Why? Because we can't turn back time and you can take a whole of your lifetime to learn it.
In this case, I'm comparing to DJ-ing which really related to producing. It's like knowing the basic genre, basic beat calculating, how to beatmatch, knowing keynote songs (and what's next song that consider to be fit to be mix by the note), how to mash-up live, etc etc. Furthermore, you'll get more thirsty of this kind of knowledge, and starting to digging the knowledge of how to read the crowd, how to get in the mix for an hour with 5 genres / wide range bpm, how to be an opener / closer DJ (these spot are much harder than guest star DJ), how to make the flows, how to get to know if you crowds looks happy or boring, and how to change that crowd goes like what you want.
Back in the days, I'm learning the basic of DJing by making podcast with Mixmeister Fusion. Firstly, I learn the basic of music anatomy (what is verse, reff, breakdown, drops, bridge, prelude, interlude, postlude, etc). It doesn't learned in months, cause it took almost 2 years, and today, I'm still learning on it (because every kind / genre of music has it's own anatomy). Secondly I've entered small gigs and start to learn how to chill myself first (yes, nervous will always there, if you're excited), and continuously learning how to read the crowds, make a flow, and all things mentioned above this paragraph. This hurts me a little bit when I know that learning the scale / keynote is so important, because when I'm a kid I'm just a drummer and never touch any piano / guitar. But as the time goes by, I'm still excited about it, want to learn it, and earn my own works as people appreciate it well.
Simply said, learning something has no "Too late" in it. Just go and be happy with it.