HAMTRAMCK, Mich. >> The prom countdown was nearly complete, the do-it-yourself Greek columns, pink and white tulle bows and plastic flutes with the “Once Upon a Dream” logo awaiting the evening of evenings.

But as she looked at her reflection in the mirror, her one-shoulder lavender gown matching the elaborate hijab that framed her face in a cascade of flowers — a style learned on YouTube — Tharima Ahmed knew that what lay ahead was more than simply a prom. As organizer of Hamtramck High School’s first all-girl prom, which conforms to religious beliefs forbidding dating, dancing with boys or appearing without a head scarf in front of men and boys, Ahmed, 17, was forging a new rite of passage for every teenage Muslim girl who ever spent prom night at home, wistfully watching the limousines roll by.

“Hi guys — I mean girls!” Ahmed, a Bangladeshi-American, exuded into the microphone as 100 girls — Yemeni-American, Polish-American, Palestinian-American, Bosnian-American and African-American — began pouring into the hall on Bangladesh Avenue.

This was prom, Hamtramck-style: The dense scrappy working-class city of 22,500 encircled by Detroit, once predominantly German and Polish, has become one of the most diverse small cities in America. Its new soul lay in the music playlist embedded in Rukeih Malik’s iPhone — Lady Gaga, Cobra Starship the Belgrade-born singer Ana Kokic and The Bilz, a Canadian-South Asian band, singing “2 Step Bhangra.”

In this season of wobbly heels and too much cleavage, the bittersweet transformation of teenagers in jeans and T-shirts into elegant adults barely recognizable to their friends is an anticipated tradition. But at the all-girl prom, there were double double-takes, as some classmates of Ahmed, normally concealed in a chrysalis of hijab and abaya, the traditional Muslim cloak, literally let their hair down in public for the first time.

Maha al-Shauweyh, a Yemeni-American who helped organize the event, arrived in a ruffled pink gown, her black hair falling in perfect waves, thanks to a curling iron. Like many here, she stunned her friends.

“It’s ‘oh my god!”’ said Simone Alhagri, a Yemeni-American junior who was wearing a tight shirred dress. “This is how you look underneath!”

The dance was the emotional denouement of seven months of feverish planning in which the prom committee raised $2,500, mostly through bake sales. Ignoring the naysayers who could not imagine a prom without boys, Ahmed and her friends approached their task systematically, taking a survey of all the girls at Hamtramck High. They found that 65 percent were not able to attend the prom because of cultural and religious beliefs. In addition to Muslim girls (and alumnae who never got the opportunity), other students wanted to go, too.

“I want to support all my girls,” said Sylwia Stanko, who was born in Poland and whose friends are mostly Bengali or Arabic. “I know how important it is to them.”

The prom promised “music all night, except during dinner and five minutes for prayer.” A former Knights of Columbus hall was transformed into princess-pink perfection, the pink tablecloths and balloons matching prom programs with cursive pink lettering.

Ahmed placed a huge order for decorations with PromNite.com, including a light-up fountain to which the girls added pink food coloring.

Ahmed had dreamed of prom night since her freshman year, squirreling away photographs of ballrooms and ads for tiaras.

As she prepared for her big night, her mother, Roushanara Ahmed, recalled the fancy pink sari she wore to an all-girls party in what is now Bangladesh.

“I was in high school,” she said, her voice low, eyes softening. “I know her feelings.”

Like the prom, the city of Hamtramck is a mixer of a different kind. Along Joseph Campau Street, a monumental statue of Pope John Paul II presides over Pope Park, with its festive mural of Krakow. A poster for the television program “Bosnian Idol” is displayed in the Albanian Euro Mini Mart, known for homemade yogurt and burek, traditional spinach and meat pies. During her English class, Ahmed can hear the call to prayer over loudspeakers from the Al-Islah Islamic Center a few blocks from school.

Diversity was hard-won: The mosque, one of five in the city, was the subject of controversy in 2004, when some people strenuously objected to the city’s decision to allow it to broadcast prayers five times a day; the city ultimately prevailed, regulating the hours when the call may be sounded.

In sharp contrast to earlier immigrants, drawn by the once-thriving auto industry, a quarter of the residents now live below the federal poverty level.

“People here have to work out their difficulties,” said Mayor Karen Majewski, an ethnic historian and Hungarian folk dancer. “There’s no opportunity to hide in your cul-de-sac.”

At Hamtramck High, which has 900 students, non-Muslims respectfully tuck away their food and water bottles during Ramadan. The prom reflects a broad cultural shift.

“Twenty years ago, parents used to pull fifth-grade girls out of school for arranged marriages,” said Chris Bindas, a library aide who brought chocolate-dipped cream puffs to the prom. “Now these same girls are going to college” — albeit a college close to home, where the girls will continue to live with their parents.

Ahmed, who plans to work while attending Wayne State University in Detroit, has applied for 27 scholarships, saving all the rejection letters.

“These are my weaknesses,” she said of her financial struggles. “But they are also my strengths.”

On Saturday night, when the strobe lights started, throwing jewels of light around the room, the shy comments of “Oh, you look gorgeous!” and “Ooh, I love your shoes!” gave way to the sheer joy of music, the girls fist-pumping in unison, some discarding their heels and some hugging one another in disbelief.

Shortly before 8, it was time for prayer, the spaghetti straps and empire waists disappearing under hijabs and abayas, a prayer rug taking its place on the dance floor.

Afterward, when the prom royalty was announced, it was no surprise — except to her — that Ahmed was pronounced the senior queen, the tiara from promnight.com ceremoniously placed atop her hijab. Amid whoops and shrieks, she struggled to maintain her composure. Her mascara was not so lucky.

Then the hall erupted with a song by the band 3alawah, and the girls performed a debka, a Middle Eastern circle dance. Everyone held hands as they snaked around the dessert buffet and columns decorated with artificial wisteria.

The jubilant energy of 100 young women feeling victorious and beautiful filled the room.

© 2012 The New York Times Company