>This part isn't true.

Perhaps. My experience was similar to yours in many respects, but very early on it became clear to me that I was a member of a very small club. We were subject to standardized testing starting in, I believe, third grade, and were delivered results that compared us to hundreds of thousands of other kids across the country. It is hard not to feel "gifted" when you are given a very officious looking document with a government letterhead and the number "99" on it (the primary metric of academic achievement was a percentile score from 1-99) every three years. What further set me apart was the honour of being the only atheist and sceptic in a religious elementary and secondary school. Perhaps I presumed myself intelligent only by virtue of the bottomless lack of rationality I was surrounded by. Overcoming Bias would have been exceptionally welcome in those days.