Olivia Rodrigo did what any 21-year-old could legally do in the U.S. as soon as she turned 21 on Tuesday.

When the "Drivers License" hitmaker opened her "GUTS World Tour" at Acrisure Arena on Friday, she shared with her audience what she did on her 21st birthday.

"I turned 21. I'm really f***ing excited about it -- big birthday," she excitedly told the concertgoers, as seen in a clip shared on X, formerly Twitter.

She continued, "I went to the gas station the other day, and I bought a pack of cigarettes and a case of beer. I promise I didn't consume it, but I bought it just because I f***ing could."

"Anyway, all this to say that I think growing up isn't so scary after all and life just kind of gets better at the end," she added before singing "Teenage Dream."

While performing her song, videos of little Olivia were played on the screen, making the number even more emotional.

A post shared by instagram

A day before her 21st birthday, the "Good 4 U" artist had a party with her friends and celebrated her last day of being underage.

Olivia took to Instagram to share some photos from the celebration and captioned it, "Today is my last day of being able to underage drink (hypothetically)!"

A post shared by instagram

Meanwhile, on her birthday, the singer-songwriter posted a photo of herself beside a five-tier cake that read "spill ur guts."

She also included an old photo of her wearing a pink birthday hat.

"21! So grateful for all of the incredible things I've been able to experience so far and so excited for all the good times ahead. Thx 4 all the love," she wrote.

A post shared by instagram

The former Disney star is currently on her first arena tour, called "GUTS World Tour," in support of her second studio album, "Guts," released in September 2023.

She is set to perform across the United States, Canada and Europe from February 23 to August 17.

For her opening night, she performed 22 songs, per Variety, including "Bad Idea, Right?" "Ballad of a Homeschooled Girl," "Traitor," "Vampire," "Making the Bed," "Happier," "Obsessed," "Get Him Back!" and "Jealousy, Jealousy," among many others.