I started playing somewhere between 1.2.5 and 1.3.2.
At first, I slowly but surely got really hooked on the game, just hearing Notch's words: "Where the only limit, is your imagination." really spoke to me; now, I am SO ADDICTED to the game, that it's the only game I play ALL DAY whenever I have the free time. Minecraft is my absolute favorite game, and ever since the 1.7.2 update, I have been playing non-stop every day when I have the free time. I have a world that I made 3 months ago when the 1.7 update hit, and I have built an epic medieval town for my survival stuff, and I am building a Skyrim-inspired city/area on a cool giant snow island I got really lucky that I found directly across the ocean from my original spawn.