It took me about 10 years of relative inactivity and curiousity about non-JW sources of information. At some point, I remember going to meetings and every time something was said that made no sense, I'd mentally refute it under my breath or in my mind to resist it undoing the things I'd learned.
Then I finally thought. Why am I sitting here listening to stuff I can refute? I still liked some of the people and the loves and hugs I'd get for showing up, but would sit there almost rolling my eyes at the dumb I was listening too, and wondering why everyone else was eating it up like it was ice cream.
It's rather embarrassing in retrospect how an intelligent person can listen to such drivel for years and never really question it, think it's utterly brilliant theology.I did that for nearly 20 years.
I actually have a fairly high IQ (134), but that's not really what it takes to get past the WTS teachings, its very much based on emotional manipulation, although there is sort of a pseudo intellectualism to the theology (like "see how we know Greek and Hebrew" and "look at these big words we use that you need to get a dictionary to understand") just enough to make you believe that they're the pre-eminent Biblical scholars of the world. Until you read some real ones, people who have actually devoted most of their lives to religious and related historical studies.
But, don't you try to be. You mustn't research anything except throught WTS publications. It's when I started breaking that rule that I began to question a lot of things. Then the internet came and I started nosing around it too. But, the good old public library was where it started for me. There's all kinds of free information there you can utterly deconstruct JW teachings with, especially when you lose that superstitious fear that everything not written by the WTS is the work of demons and apostates and the Antichrist, all determined to undermine your faith in Jehovah.
I soon found out 607 BCE and 1914 were utter crap, pulled out of someone's gin soaked dreams, no doubt. Without that in place, the whole thing is a house of cards, really. Pull one out and down it goes.