I read this a while ago, but I've been saying and thinking something like it for a while:
"Where did Trump acquire his appreciation for the power of fear and his bullying ways? As his biographer, I locate the key moment in the summer of his thirteenth year, when his exasperated parents notified him that he was being sent away to military school because he was too unruly. Cast out of the family home, he did become more disciplined, but he also became the man who would tell me he enjoyed "all types of fights, even physical.""
I've read that when he was 13 he skipped school a bit and went into NYC with a friend. I suspect that something went on there that was more than being "too unruly." Skipping school might be enough, if it was a matter of endangering progression to the next grade. I suspect it was something more, possibly criminal, that went on in that time frame. My $0.02.