Confession time: I started role-playing with M.A.G.U.S., a Hungarian-made version of D&D, when I was about 14 or 15. I have played a lot of things since (I'll spare you the math, it's about 14 years). Although I attempted once early on to get my hands on a D&D rule book and read it in English (not easy!), it didn't quite happen until I was in college and studying in the USA. With that in mind, the following answers all refer to my actual D&D experiences in the past 5 years, not my role-playing history in general.
Here it goes:
Day 1: First person who introduced you to D&D? Which edition? Your first Character?
I remember hearing that M.A.G.U.S. was "like D&D" very early on. Once I got my hands on a rule book in the US, I mostly taught myself. I started with 3.5, and it's still my favorite edition. The first time I played, I was the DM. (I'm a storyteller. I'm always the DM...) The first character I made was a Factotum. Go figure.
Uh... a lot of people? In 2012 at ETSU we had an RPG class in the Storytelling program, and that class had 16 people in it. Some of them were practiced, some of them were new. We played 3.5. Definite crowd favorite was Amadeus, our half-orc barbarian with an Intelligence of 3, and the heart of an angel. I also quite loved Iron Fist, our Fighter/Dungeoneer who was incapable of rolling a success whenever it came to kicking down doors. It was a running joke.
Day 3: First dungeon you explored as a PC or ran as a DM.
It was a campaign called "Eye of the Storm" I made up. Characters stuck in a guest house high in a mountain pass during a snow storm. They explored the natural caves under the guest house and discovered all kinds of nasty things. They also invented Molotovs at some point.
Day 4: First dragon you slew (or some other powerful monster).
Whew!... Again, I am usually the DM. I guess the biggest kill I participated in as a player was the legendary Questing Beast from a couple of weeks ago. That sucker was HARD to kill!
Day 5: First character to go from 1st level to 20th level (or highest possible level in a given edition).
Honeybadger, my current Pixie Barbarian, is on her way to fame. She just leveled to 11th. She started on 3rd, though. Again, I blame the Questing Beast. This is 4th edition.
Day 6: First character death. How did you handle it?
None yet! Honeybadger went below 0HP once for a few nerve-wrecking seconds, but miraculously avoided death. I am also a DM with 0 character deaths on my ledger. I am not letting them get away that easy.
Day 7: First D&D Product you ever bought. Do you still have it?
Dice! Definitely dice. And yep, still got them. My players love them because they can't roll for ****. Makes my NPC's look like I got them on craigslist. But they have nostalgic value.
Also, interestingly, the first rule book I purchased was Al-Quadim. Found it in a used book store for 5 bucs. That's right, hate me.
Day 8: First set of polyhedral dice you owned. Do you still use them?
See above! :) Nice set of light blue sparkly ones. Bought them in New York City, baby.
Sadly I still have not gotten a campaign together for Al-Quadim (as a storyteller I have a slight Arabian Nights fixation). As a player, my first consistent campaign is happening right now, in the world of Exalted out of all places... Shaping up to be tons of fun.
Day 10: First gaming magazine you ever bought (Dragon, Dungeon, White Dwarf, etc.).
None for D&D, sadly. I got to get on that sometime. We had one for M.A.G.U.S. called Rune.
Stay tuned for Part 2!