My earliest memories were trying to watch TOS and TAS through the non-cable, rabbit ear TV reception of the mid to late 70s. Also, two of the people in my household were not scifi fans so my older sis and I had to struggle to watch it till I got my own TV. She was the one that got me into scifi in general. I didn't become a full fledged Trekkie till 1983 though. I recorded episodes on analog audio tapes, I listened to STII and III on audiotapes from movie booklets before I saw the movies themselves. I watched the show on my little 13" b&w tv then a 13" color TV by about 1982-83.
That all seems long ago, but I've mentioned on here that I distinctly remember becoming a "Trekkie" proper in 1983. Before that i would occasionally watch episodes on Saturday or Sunday, but then one night after watching back to back episodes it literally HIT me...these episodes were so good I felt a new level of appreciation. I started to look at the midnight showings of ST EVERY night ( I finally managed to see EVERY one of the 79 episodes, the last two I saw were The Changeling and The Cloudminders), got audio tapes and records, I saw STII shown first in school on a projector, then finally in 1984 in June I saw STIII in a theater..a first, it cemented everything. It's been downhill ever since!