Bonnie Linder waves to a school bus full of kids every weekday from her home in the small town of Hartley, Iowa. Last week, the kids and their bus driver wanted to do something special before she turned 93 that weekend — so they surprised her with a sweet birthday message.

On Friday, Linder was standing on her porch and waving to the school bus heading to the local elementary and middle schools when the bus slowed to a halt and the kids yelled, "Happy birthday!" out of all the windows. She was clearly overjoyed by the surprise, laughing and exclaiming, "Oh my land!" in a video captured by her daughter, Judy Zimmerman.

Linder's other daughter gave the bus driver a "heads up" about her mom's birthday in advance, but she had no idea she would be getting such a sweet shoutout, according to Zimmerman.

THIS is my HAPPY today!!!!!! Posted by Judy Zimmerman on Friday, March 13, 2020

"Mom had NO idea...and the morning sun could NOT have been more perfect!" Zimmerman told CBS News. "Although you cannot see her face, she was SOOOO HAPPY!!! The kids all were in on it with the bus driver and were excited to be able to stop!"

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Linder first started waving to the school bus at the beginning of this school year. "She sits in her rocking chair at her picture window and looks down the gravel road to watch for it," said Zimmerman. "On a good weather day, she will step out on her porch and the bus driver will honk as they drive by."

In addition to her school bus greeting, Linder gives a morning greeting to three other people every weekday, Zimmerman said. Linder waves to one of her daughters as she goes to work, the mail delivery woman and a man hauling a cattle feed wagon as they all pass by her home.

Linder's morning routine will be interrupted for the coming weeks, however. Schools in the Hartley-Melvin-Sanborn community school district, where the morning bus takes students, are "closed indefinitely" amid the coronavirus outbreak, according to a Monday post on the district's Facebook page. The school district said it will be following Iowa Governor Kim Reynolds' Sunday recommendation that the state's schools shutter for four weeks "at this time," according to the post.

Zimmerman said her mom will "continue her wave, but one less for a while!"

Millions of American students are remaining home due to the coronavirus pandemic. As of Tuesday morning, there have been school closures in 37 states impacting over 37 million kids. New York City schools, the largest school system in the U.S, closed starting Monday.