I honestly don't remember becoming a fan, since it started when I was ridiculously young. When my family went out of town shopping (because we lived in the middle of nowhere, it was a big deal), Dad would buy me some type of die-cast Hot Wheels or Matchbox car, since he was into those. I was big into construction equipment, and so one fateful day, when I was 2-ish years old, he got me a dump truck with a pull-back motor that turned into a robot. You may now recognize him as the orange Moto-Bot Dump Truck by MCToy. I still have him, as well as a complete set of all the Moto-Bots, campy as they can be. From there, it spread to all the garage-sale G1s and GoBots anyone in my family could get my hands on. It really solidifed when G2 started, and I could buy TFs in stores. All my relatives coordinated with my parents on Transformers for my birthdays.
I've been a lifer ever since, without breaks, even though I took crap about it through middle and high school. Unfortunately, I have a congenital disease known as "completism"... I have to have them AAAALLLL. I play with mine though. I open the new ones and buy the old ones loose. I can always enjoy beautiful sealed figures in pictures of Skywarp408's collection, but I can't transform them if they're in the package!
I had a similar start with Legos around the same time, with the Precinct Cruiser, set 6506
, but the TFs rooted deeper