Until recently I assumed the statute of limitations on my chances of becoming a "Doctor Who" fan had long since expired — sometime around the decline of communism and the rise of Sir Mix-A-Lot, if I had to guess.

Simply put, the series — which celebrates its 50th anniversary on Saturday (yes, it debuted in England less than 24 hours after JFK was shot) — never spoke to me. The few times during the 1970s when I tried to watch (always after school, always in the unexplored country of PBS afternoon programming, always when the Brady Bunch were visiting Hawaii in a rerun), it felt impenetrable. What's a "TARDIS"? And a "Dalek"? Are those the robots on wheels that look like portable gyro-slicing machines? What's with the flying phone booth? And this "Doctor," curly haired with a folk-singer scarf and wild, bug-eyed glint? What's he a doctor of? Was he actually Donald Sutherland? Or that hairy, limber hippy from progressive '70s sex manuals?

No, I would not be a Whovian.

Decades passed before I gave "Doctor Who" another thought.

Then, around the 47th year of the show's existence, I began to run into friends, relatives and acquaintances all inexplicably obsessed with this sci-fi eccentricity. Largely dormant for the 15 years prior, "Doctor Who" had been rebooted in 2005, and, despite the age of the franchise, was becoming a late-blooming phenom, one of the most popular TV shows in the world. It's so successful by now that its anniversary will be marked with a hugely anticipated "Day of the Doctor" special airing Saturday, Nov. 23 on BBC America and Nov. 25 in movie theaters nationwide. Even more unlikely for such antique, nerdy pop wallpaper: Its newest, biggest fans were female.

Intrigued, I decided to wade in to see what I had been missing. And immediately, I was startled: Here was a show with decades of plot, operating in a genre not known for accommodating dumb questions, and yet "Doctor Who" — both the fandom and the unexpectedly cheerful series — was generous, accommodating.

Take Mindy Laff, a 50-year-old Chicago docket manager for intellectual property lawyers. I told her about my persistent allergy to her favorite TV show, and — unlike the sneering, sighing misanthrope I expected — she sympathized. She had recently become a Whovian herself: "I've always liked geekdom, but I found sci-fi communities impossible. So cliquey! I was intimidated. I didn't hate the show. But 50 years of story? Really? And, like, 200 plots? And I would have to learn about each Doctor? There are more than one? And know his companions? And the 130-something missing episodes that fans have somehow reconstructed? And the spin-offs? And the Christmas specials? I have patience issues! I already have a bunch of comedy podcasts I want to listen to, and when my parents ask me to dinner, I say 'But I have all this TV to watch …'

"No, no: I couldn't add 'Doctor Who' to that. Then a year ago I met some 'Doctor Who' fans and asked them how to get into it. And they said: 'What can we tell you?' They were so nice to the casually curious."

Sounds suspiciously like a cult? Well, yes.

I am a Whovian now.

A Whovian poseur, perhaps. But I aspire to pure Whovian. If the Whovians will have me.

Here's how it happened: I started by soliciting Chicago for tips on how to get into "Doctor Who," and there was no shortage of advice. But it was always the equivocal and relatable kind: You can't watch the show wrong (but usually you can watch it out of sequential order), it's cheesy (but deep), corny (but profound). I was offered lists of episodes to watch (and not watch). For emotional support, I was sent links to fan forums.

This is not an uncritical fandom: Jennifer Kelley, co-founder of Chicago TARDIS, one of the largest "Doctor Who" conventions in the world (happening Nov. 29-Dec.1 at the Westin in Lombard), said: "If anyone tells you they like everything about 'Doctor Who,' be suspicious."

Throughout the '90s, and as late as 2004, interest in the BBC-born series had waned so severely, Kelley said, that she assumed her then-modest four-year-old convention was on its last legs. The fandom had become cloistered. Even as I got started, when a fan told me to watch "series five with the 11th Doctor" and I asked for clarification, they had to explain that Whovians refer to seasons of the new show as "series" but seasons of the original 26-year run as "seasons."

Huh.

Generally, though, the Whovians — earnest, a touch twee, too fast to laugh at its inside jokes — was ridiculously well-prepared for wannabes. "The wonderful thing about the 'Doctor' is it changes tone, style and narrative so often that if you don't like it one week, you might love it the next," said Paul Booth, an assistant professor in DePaul University's College of Communication who studies cult TV fandoms (and also edited "Fan Phenomena: Doctor Who," part of the University of Chicago Press' new series of books on fan culture).

Allegra Rosenberg, an 18-year-old Skokie high school student who developed a sizable online following for her "Doctor Who"-inspired ukulele ballads (later employed by BBC America in the marketing of the show), sent me a three-step indoctrination regimen. Step one was: "There's nothing much you need to know …"

Nothing at all, other than, she added, the following: "The basic process of regeneration (when the Doctor switches bodies, in a trick of alien biology), and the fact he travels though time and space in a blue (British) police box — all things you probably know already though pop-cultural osmosis, so you're good to go."

I began with "The Aztecs," a four-parter from 1964 that looks as though it were shot, well, at your local PBS station. The Doctor (who has no name, only a title) was William Hartnell, the first Doctor, then in his 50s, though looking much older. He lands in a 15th century Mexico recreated on a BBC budget, by way of an over-lighted soundstage. He finds himself witness to a human sacrifice. He's abrasive, impatient. At the end, having prevented the sacrifice but failing to dissuade Aztecs that killing a man will bring rain, the Doctor is asked by a companion time traveler, "What's the point of traveling though time and space if you can't change anything?" And the Doc says, sincerely: "You failed to save a civilization but at least you helped one man."