Up until a few months back I had not touched a keyboard of any sort other than playing chopsticks and learning Axel F, about 25 years ago.
I bought a few books on theory and chords and how to write songs and an 'Idiot' guide to music creation. That part, I think, is down to me just getting on and reading it - chord progression, chord types, modes, keys, time signatures, circle of fifths, etc. I've certainly learnt a load since reading them by dipping in and out and can even knock up a tune, now, to some degree.
However, through trying to put these examples into practise I've already started to get into some bad habits - a 'C Major' chord with my right hand using fingers 1, 2 and 5. Instead of 1, 3, 5 because it feels more natural and easier. Though, I know further down the line this is going to be a problem, if I need to start reaching for the bigger chords like 7ths and onward.
I plan to take one lesson a month. I've only had one, so far. Hopefully, enough to keep me on the straight and narrow. Half the lesson is me being told off for what I've done wrong and the other half with me asking a bunch of questions. It's probably far from ideal but, like you, I have no interest in classical music. Who knows how many bad habits I will pick up without someone who actually knew about such things.
One of the hardest things I've had to deal with is fully-weighted piano keys Vs. the semi-weighted keys of my synth. It just feels weird!