I think my ability to hold generally got better as I got older... but I'd always rather pee outside than wet myself.
Nothing specifically got me "into it" at school... my first memory of being fascinated with pee was sitting in my bedroom late at night, the girls in the house behind having a party in their garden and just peeing off the decking, butt's in full view of me some 50-60 meters away.
Never deliberately went to see "how high" I could get it, but I did do that once in a school urinal with a few friends... seeing who could get it highest up the wall...
Never really foug