I was six when I had the certainty that mummies in Museums must be sources of knowledge and power, by eight I was talking to spirits, started soul travelling (I invented a method that I later found was identical to the concepts in core shamanism, I used an elevator, they use a tree or mountain) and doing spells using sympathetic magick.
Around the same age, I also somehow knew it was important not to become dependent on mundane pleasures and would intentionally skip doing things I wanted to develop that muscle of self-control, and I knew without knowing how that an image could be used to summon a spirit to be present, which I posted a bit about here.
It’s hard to say where I learned it, it just kind of seemed normal and natural, and I worked in elements from books (like The Moon Of Gomrath) and later, The Golden Bough, and then I created my own systems based on that and on what seemed to work best.
I never knew magick was a real thing people did outside books and movies (where magick was usually considered evil, and good mages must only exist to keep black mages from taking over etc.) until I was older, I thought it was just me and I was alienated and weird enough to be able to handle that, to keep it in a kind of kitty box and then bring it out and use it when needed. Everything I did was kept secret, I had no-one to talk to about this, and my family would have freaked out!
This is why I support BALG and any similar movement to say that magick is natural, normal, and part of human life, that it can be learned as one learns language or a musical instrument, because that cat needs out the bag (or box lol) and this includes for my own future incarnations, because I plan to reincarnate and leave some breadcrumbs for myself.
Every one of you that I can get busy writing books or going public, I do for you, I do for mass theogenesis (my manifesto) and also, equally, for my future self. 
Humans have got to evolve or they’ll forever be warring for retard-level resources and following psychotic men who have sky daddies telling them they’re the only ones with access to The Truth.
Oh and finally. from what I recall in BALG videos, I think E.A. got started the same way, a little scamp trying to make his Lego blocks levitate and stuff, it just seemed natural to him.
When it comes to books, I prefer to use my leisure time on other things, most of my YouTube use is “what’s in my bag” and home-maker channels, not dark darkness and most forbidden rites 
- different strokes for different folks! Any grimoire i do read, I end up wanting to modify it and improve it, I’m kind of not able to follow anyone else’s systems to the letter.