I got the Basic set for Christmas 1980.
Prior to this the only xp I'd had with the game was leafing through a few of the 1e books in the book stores at the mall that summer.
I'd gathered that it was a game of some sort. But I couldn't really digest it in the brief time in the stores. And they never seemed to have all/the same books. So it was a bit like that story of the blind men & their elephant descriptions. But, like I said, I'd gathered that it was a game of some sort & it seemed pretty interesting - dragons, Norse Gods, Elves, a book of monsters....
So come Christmas list making time I put "Dungeons & Dragons - game" on my list.
Grandma got it for me. Well, what she ordered (presumably from the Sears or JCPenny catolog) was the Basic Set. She had no idea that there was a whole series of books. And I had no idea that there was a boxed set. Neither of us realized there was any such thing as a difference between D&D and AD&D.
Christmas day I ripped the wrapper off the Basic set.
And after dinner my brother & I went to play it & realized that there was way more to this thing than any other game we'd ever played (well except for some of our Dads Avalon Hill games - we'd played a few of the simpler ones with him).
This was going to take a day or two to figure out. Oh well, there was plenty of other stuff to play with for the moment.
Once we got home from Grandmas I spent the next day or two reading the Basic book, reading B2, & fiddling around making characters.
A day after that myself, my brother & our cousin started to play. I was the DM by default as it was my book & I'd read it all.
Not one drop of D&D experience between us.
That's right, 3 average 10 & 11 year old kids figured out how to play all by themselves.
We knew no one else who played. The other two had never heard of the game. And my only exposure had been flipping through pages at the book store that previous summer.
A short time later we'd add our one friend to the game.
Starting from complete scratch was not hard.
It was just like playing with our Star Wars figures - minus the figures, but plus dice rolling to see if attacks hit/miss etc.
The only thing we weren't quite sure about initially was if we needed some sort of board or not. You know, since it was some sort of game. But we'd figure that out soon enough.
Of course, being 10 & 11, our story telling skills were pretty awful.

But we had fun & easily figured out the rules.