I watched TOS in repeats with my older brother. I must have been kindergarten age when I first watched Trek because in first grade I was already such a fan that I wanted to go as Spock to the school carnival. My mother made some Vulcan ears for me out of cardboard.
Sadly, none of my classmates recognised the costume and, what's worse, when I told them that I was Mr. Spock from the Enterprise they just gave me blank stares. Apparently, they had all lied about how often they watched TV from the West (this was in the GDR). I remember being quite astonished by the fact that there were people who didn't know what Star Trek was.
A few years later, TNG premiered here and I watched all Trek shows in their first run here.
My mother watched what I assume was the original run of TOS here when she was pregnant with my older brother, so in a way, Star Trek has been with us for a long time.