When Elizabeth first told us that she wanted to become a cheerleader, we thought it was a joke. We didn't think that in the universal way -- "L.A. traffic is a joke," or "NFL preseason games are a joke," or "Leading off Alcides Escobar is a joke," -- we actually thought she was joking. Elizabeth has a dark and wry* sense of humor. Saying that she had decided to become a cheerleader seemed like her ultimate punchline.

*I actually spelled this as "rye" at first, and it took me way too long to realize that it was wrong. As far as I know, Elizabeth does not have a rye sense of humor, it's much more focaccia.

I've written a lot about Elizabeth through the years, and there are times when I look back at stories like Katie the Prefect or The First Goal and barely recognize her. This is a good thing, I realize. It would not be great if 17-year-old Elizabeth was still the girl who was paralyzed by the decision to buy either a toy owl or a bag at Harry Potter World.

Still, a few people pointed out to me that one of the key points in Katie the Prefect is that Elizabeth was a Ravenclaw. She is now a full-fledged Slytherin, and has been for a few years -- she's so devoted to the Slytherin cause that she has now filled her room with various green Slytherin items.

Slytherin, you'll know if you're even a slight Harry Potter fan, is the darkest Hogwarts house, the house of He Who Shall Not Be Named (John Elway) and various Death Eaters and Severus Snape and, um, oh yeah, Lin-Manuel Miranda.

https://twitter.com/Lin_Manuel/status/779083017721524226?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E779083017721524226&ref_url=http%3A%2F%2Fjoeposnanski.com%2Fmy-pal-lin%2F

I am a Gryffindor. This is the heroic Hogwarts house, this is Harry Potters' house, the house of his parents, Dumbledore's house, and so on. Every Harry Potter test I've ever taken has shown me to be a Gryffindor. Every Harry Potter fan I know has said to me, some with disgust, "Oh yeah, you're a Gryffindor."

https://twitter.com/JPosnanski/status/779141267674497024?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E779141267674497024&ref_url=http%3A%2F%2Fjoeposnanski.com%2Fmy-pal-lin%2F

Gryffindors and Slytherins are natural enemies. Even though, yeah, I'm going to link this again.

https://twitter.com/Lin_Manuel/status/779141624052023299?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E779141624052023299&ref_url=http%3A%2F%2Fjoeposnanski.com%2Fmy-pal-lin%2F

Elizabeth becoming a Slytherin reflects pretty well her evolution as a young woman. The uncertain little Ravenclaw began to explore the edges, began to ride roller coasters, began to embrace horror movies, began to speak out strongly against injustices in the world. In time, she became THAT girl, the dark and brooding girl who wears black and rages against inequality and likes Westworld.

It happened slowly and all at once, which I suppose is what it's like being a parent. The other day, my wife Margo found an old Flip Camera, and on it we found dozens of videos of Elizabeth and our younger daughter, Katie, from a decade ago, and we watched Elizabeth sing and dance, and she was wearing bright colors, and she sounded like a record at 78 rpm* and we wondered -- not sadly, but with real curiosity -- what happened to that girl.

*I'm so happy that vinyl is becoming cool again and I can use old record references.

So when Elizabeth said that she was becoming a cheerleader, we thought she was joking ... and we could not think of a better joke, really. It was as if she had spent the first 16 years of her life setting up the punchline. She loathes sports, peppiness, dancing, exercise, skirts and most outdoor activities. Elizabeth as a cheerleader? The image had all of us laughing for weeks. We created -- and Elizabeth was one of the co-creators -- an image of Elizabeth the ironic cheerleader; she would be the one standing apart from the others muttering, "I just don't see what the big deal is, score, don't score, whatever."

"You realize that if you're a cheerleader, you're going to have to smile occasionally," we would say.

"I'm going to see if I can work around that," Elizabeth said back.

It was a hilarious bit, and Margo and I often told it at parties -- people who know Elizabeth couldn't get enough of it. Our daughter the cheerleader. Endless comedy material.

See, but here was the thing: She kept going through the process of becoming a cheerleader. All her life, when Elizabeth showed interest in something -- the brief time she wanted to play the guitar, her short dalliance with softball, the Dungeons and Dragons girls club she joined, on and on -- she relied on us to make every detail happen. But with cheerleading, because we honestly thought she was joking, we didn't get involved. We didn't remind her about it. We didn't help her figure out the details.

And so every step along the way we were surprised. Elizabeth told us that she had informed the coach that she was going to try out. We smiled. She told us that a couple of her friends had decided not to become cheerleaders. We nodded knowingly. She told us that the tryout date conflicted with one of her final exams, but that she had talked to the coach about rescheduling for her. We began to wonder what was happening.

Then, one day, Elizabeth was a high school cheerleader.

The next day, she came home wearing her cheerleading outfit, and she was glowing like the tesseract from the Avengers movies.

The next day, she was in her room working for hours on getting the cheers exactly right -- "Hey, you know the story ... everywhere we go it's Chargers territory!"

The next day she was getting her hair cut so that she could put it up in a ponytail with the red bow that cheerleaders wear.

And all of it, every single minute of it, made her boundlessly, inexhaustibly, tear-jerkingly happy. It isn't that Elizabeth has been an unhappy person; she's as happy, I imagine, as any other 17-year-old girl. But this was a different kind of happy, the sort of happy we saw on that magical day in New York after we went to see Hamilton.

What sort of happy? There's a great moment near the end of the A League of Their Own, where Evelyn misses the cutoff again. You'll remember that the first time Evelyn missed the cutoff, Tom Hanks launched into his legendary "There's no crying in baseball," bit, which made Evelyn cry more, which caused an umpire to say to him, "Perhaps you chastised her too vehemently," which caused Tom Hanks to say, "Anyone ever tell you you look like a penis with a hat on?" which led to Hanks getting ejected.

Anyway, second time Evelyn misses the cutoff, Tom Hanks -- because he has changed and grown to respect the women on his team -- holds back his fury and says in as measured a tone as he can manage, "You're still missing the cutoff man. That's something I'd like you to work on before next season."

And after he says that and she thanks him, Hanks begins to shake violently, because the emotion shoots through him like jolts of electricity.

THAT'S how happy Elizabeth is with cheerleading. Like happiness jolts through her.

She hasn't changed her persona, understand. She's still the edgy one with the piercing jokes and sarcastic view of the world. She still wears her ironic black T-shirts and likes her dark DC Comics villains and wants to march for every cause imaginable. But she's learning one of the greatest lessons a person can learn. We're all more than one thing.

On Friday night, Elizabeth cheered at her first football game. I took a photo from as close as she would let me stand, which was very far away. The photo is terribly out of focus. In so many ways that makes me love it even more. I put it through a pastel filter.

All game, Margo and I kept asking each other, "Doesn't this feel like an alternate universe?" The game, I should say, was interminable, a combination of first-game rust and referee burlesque; it lasted, best estimate, 33 hours. Through it all, Elizabeth smiled and cheered and synced and looked like there was no place on earth she would rather be. She looked like she did on the night of Hamilton, only the feeling was not fleeting. Margo and I sat on the impossibly uncomfortable bleacher benches and our backs were hurting, and we were starving, and Elizabeth asked for the defense to go, and we were practically in tears because who knew, who the heck knew, that this is where our oldest daughter would find one of her true selves?

"How was it?" I asked Elizabeth afterward.

"I thought those last four minutes would never end," she said. "Football is so stupid. Can you keep the clock going, please?"

And then she radiated her happiest smile, our Slytherin cheerleader, at one with the world.