RESTON, Va. — The tween girls in this classroom – with their braces and sparkly sweatshirts and the bangs hanging over their eyes – don’t really know anything about the staggering level of sexism in the tech world.

They’re turned off by computer science not because of the ugly Gamergate scandal, the bro culture of Silicon Valley or the alarming statistics that show that our fastest-growing, most lucrative industry is more dominated by men now than it was in the 1980s.

No. Most of the girls who signed up for the Hour of Code class at Langston Hughes Middle School think computer stuff is “geeky” (said to me using air quotes made by fingers with sparkly nails). Taylor Swift doesn’t write code.

Elizabeth Vandenburg is having none of it. She is working at ground zero – middle school – of the women in technology movement.

This is where it begins, where girls have aisles and aisles of pink toys and clothes and phones and computers shoved down their throats and are made to believe that technology is something they consume – not create.

So right there in Reston and other towns across the country, girls are being given the chance to sit in a room full of other girls and code.

No judgment. No labels. No grades. Just turn on the computer and try this coding program.

“Coding is the 21st-century language,” Vandenburg told them. “And if you want to go into fashion, computer design, psychology or health care,” you’re going to have to be able to speak it.

Not understanding coding may be akin to illiteracy in the future.

The teachers watching the girls said they immediately saw a different dynamic in an all-girl group.

When it’s mixed-gender, the boys almost immediately turn the girls into data-entry clerks. And the boys do the creating.

That’s how it winds up working in the real world, too. Women doing the creating make up only about 25 percent of the tech workforce, like the tiny numbers of women in company boardrooms and Congress.

But what’s even more disheartening is that unlike the other places – where the numbers are slowly increasing – the presence of women in technology is shrinking. And if trends continue, these girls will barely have a part of this new, booming economy. It’s like we’ve completely reconstructed the “Mad Men” era – only with characters from “Halo 5” – in the very field that will be our future.

But in an all-girls club, the girls do all the work. And a future of equality seems a little more possible.

“This really is kinda cool. It’s not really hard,” said Kaylin Jeong, 12, one of the girls who admitted to me that she thought this whole world was pretty nerdy.

“I love this! I want to sign up for a class. Now!” said Brieauna Johnson, 12, who just learned to code elements into the “Flappy Bird” game. “It’s like this door was opened today.”

Next to her was Pradeeti Mainali, 13, who is enrolled in a computer science class because of a scheduling foul-up. Now she wants to learn more about coding, even though her ultimate goal is to become a hematologist or oncologist.

“I know computers are going to be part of all of that,” she said.

I asked her if the boys she knows are into coding.

“Nah. All they want to talk about are shoes. Like, they show me these shoes they said cost $400. Whatever,” she said, and went back to her screen.

Slowly, with squeals and cheers and whoops, two dozen girls learned that the technology that they have been familiar with doesn’t always have to tell them what to do. They can actually have dominion over it.

Little lessons in female empowerment through flappy birds, monkeys and puzzles erupted everywhere.

“This is what the boys are talking about? This isn’t that hard,” said a girl who told me at the beginning of class that she thought coding was the secret language of boys.

One of the main proponents of the “geeky” label explained to me that computers and stuff just aren’t cool. Sports are cool, said this girl, who does dance, basketball and softball. I came back to her after 30 minutes.

“I can make an app! I can create my own app. I can program all kinds of stuff,” she told me. “How cool!”

“Geeky”? Nah, your future, girls.