Mollie Tibbetts would have turned 21 years old today.

Around the U.S., people are committing 21 acts of kindness or donating $21 today in University of Iowa student Tibbetts’ honor. Donations will go toward the restoration of the Brooklyn Opera House or the Mollie Tibbetts Memorial Fund for Child and Adolescent Psychiatry at the UI Stead Family Children’s Hospital.

Tibbetts’ 21st birthday celebration will be held from 4 to 6 p.m. today at the Michael J. Manatt Community Center in Brooklyn, Iowa. The event is hosted by Mollie’s Movement: Paying Kindness Forward and the Brooklyn Opera House.

Tibbetts went missing on July 18, and her body was found after more than a month of searching on Aug. 21. Cristhian Bahena Rivera was charged with first-degree murder in the case, and his trial is scheduled for Sept. 4.

This is the first year family and friends will celebrate her birthday without her.

Mollie’s Movement was founded by Joy Vanlandschoot, the owner of a print shop in Tibbetts’ hometown of Brooklyn, Iowa. Her print shop created missing posters during the search effort. 

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Mollie’s Movement now serves to spread awareness and help find other missing adolescents across the country and sponsors the social-media hashtag #MilesforMollie. Runners dedicate miles completed to Tibbetts, who was a runner.

Around a month ago, Vanlandschoot reached out to the Tibbetts family to speak about having a celebration for her 21st birthday. She knew about Tibbetts’ love for the arts, and with a view of the Brooklyn Opera House restoration right outside her window, Vanlandschoot decided it was the perfect way to get the community involved in keeping Tibbetts’ memory alive.

Tibbetts’ cousins organized an effort in Iowa City. Select businesses in eastern Iowa with a Mollie’s Movement poster up agreed to donate 10 percent of profits on her birthday to the Tibbetts Memorial Fund for Child and Adolescent Psychiatry.

“I feel like it’s necessary to remember someone for all they are,” Vanlandschoot said. “We should remember her faith, kindness, and love of the arts. This is a great time to honor that.”

Brian Manatt, the president of Brooklyn Community Development, oversees the restoration project. He agreed to the idea with one condition: It’s a celebration of Tibbetts’ life, not a fundraiser for the Brooklyn Opera House. 

RELATED: Tibbetts trial moved to Woodbury County 

Manatt spoke with the father of Tibbetts, Rob Tibbetts, about the idea. Manatt was sold on the celebration idea after hearing Rob Tibbetts speak about his wish to ensure his daughter is remembered as a positive light rather than as a victim.

“He can say he raised a wonderful young woman,” Manatt said. “We are proud to be part of remembering how Mollie was a person.”

Restoration for the Brooklyn Opera House began in 2014. Officials have raised more than $2 million and are expected to reopen the facility at the end of this year.

Rob Tibbetts remembered his daughter in a press release for her birthday celebration.

“Mollie was extraordinary in so many ways, but her gift was her genuine interest in the people she met,” Rob Tibbetts said. “She saw in us all our best qualities and characteristics — our most heartfelt desires and aspirations and all the things we love about the world. Mollie took those things and made them her own, in her own distinct way. In doing so, her life was an evolving tapestry of the very best of us. Mollie was an irresistible reflection of everything we love in ourselves and why we will all love her so dearly for the rest of our lives.”