Whether you were there from the beginning in 1966 or found Star Trek some time in the '70s (or before we got films and TNG) it was a likely a pretty special time: discovering Star Trek when it was pretty much the only game around.
There was other sci-fi, of course, on film and television, but for a lot of us most of it paled in comparison to TOS, For myself, at the time, about the only thing I could enjoy (almost) as much as TOS was UFO. As the '70s progressed and I became more aware I started to appreciate other things, but back then TOS ruled.
The first merchandise I remember that fuelled my interest (besides reruns) were the early AMT model kits and the James Blish adaptations. Not long after I got into TAS and the Alan Dean Foster Star Trek Log adaptations as well as some of the first original novels. The Making Of Star Trek was like a bible to me. And soon Franz Joseph's Booklet Of General Plans and Star Fleet Technical Manual and Bjo Trimble's Star Trek Concordance were added to my small library. Additionally I drew like crazy: lots of starships and other stuff.
Being a Star Trek fan then you could get labelled and teased (to put it kindly) but, man, it was still a great time and a helluva lot of fun.
That could almost be me talking. We had the same experiences at the same time.
Add me to the list. It was in November 1975 that I became hooked on Star Trek. It was in December that I started buying the Blish books (#4 and #6). I couldn't wait to see the episodes I'd only read about. It took YEARS to finally see the first half "Conscience of the King" (ST was shown on two different channels - one at 4:30 and the other at 5:00).
I was pretty Trek-obsessed in junior high and high school, and was walking on air when I got to attend an afternoon "Star Trek Festival" in Calgary in 1979, when George Takei was the guest. Unfortunately I didn't get to meet him - I was coming down with the flu that day (hadn't realized I was so sick that morning before the drive from Red Deer), and by the time he was ready to sign autographs I was too dizzy to stand up. So I never did get to meet him, or any other cast member.*
*unless you count Bjo Trimble and David Gerrold, who had cameos in TMP and Trials and Tribble-ations.
I had a couple of friends who were into the show at the time, but over the years they drifted a bit away from it. Even then I think I was more into it than anyone else I knew.
I could also feel a bit isolated. I started to learn of fandom through David Gerrold's books like The World Of Star Trek, but this was all still twenty years or more before the Internet. So all I had were books and Starlog magazine.
Yep, Starlog was my monthly lifeline to Star Trek. Strange to think it's all available online now, along with so much of the fanfic I'd read about in Star Trek Lives!
and despaired of ever finding. But eBay and other sites have been helpful to me in my decades-long hunt for fanfic, and some other classic stories (ie. Kraith) are available for free online.
I honestly don't think I'd be so much into it if I'd grown up later, after there was so much that was easily available. I remember one time, on a Saturday in a store that no longer exists, when I found the first New Voyages anthology. I remember thinking that $1.50 was awfully expensive for a book (back then it was, especially for a kid whose only spending money came from babysitting for 50 cents an hour), but I was ecstatic to find it.
I still remember the Christmases when I received some of the 8" ST figures, the first Puzzle Manual, a Star Wars blanket - all of which I still have. My grandmother and great-aunt were incredibly supportive of my interests (my grandmother gave me the ST stuff and my great-aunt gave me the blanket and a space-themed notebook "for my outer space stories").
These are 30-year-old memories, and they're very precious.