Olivia Rodrigo Shares Cap and Gown Graduation Photos: 'Bye High School'

Olivia Rodrigo is officially a high school graduate!

On Saturday, the 18-year-old singer and actress posted photos celebrating her latest milestone on Instagram. "Bye high school!!!!!!!" Rodrigo captioned the carousel of three images, wearing her cap and gown as she threw peace signs and struck a silly pose. Also in the post was a photo with "Just Graditated!" jokingly written on the back window of a car.

Along with fans, several of the singer's High School Musical: The Musical: The Series costars commented on the post to congratulate her on receiving her diploma.

"Proud 😢," Frankie Rodriguez said, while Dara Renee wrote, "CONGRATULATIONS QUEEN!!!❤️🔥."

Julia Lester added, "😭😭GO LIV," and Joe Serafini also commented, "congrats liv!!!!!! 💜."

Graduating high school wasn't Rodrigo's only big accomplishment this year. After releasing her single "Driver's License" in January, the song debuted at No. 1 on the Billboard Hot 100 chart in the United States, on top of claiming the record for the biggest weekly streaming debut with 107 million worldwide streams — 76.1 million from the U.S. alone.

The post-breakup ballad was followed with the announcement of Rodrigo's debut album Sour, released May 21. The 11-track project also features other hit songs, "Deja Vu" and "Good 4 U."

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Rodrigo also put her songwriting skills to use for her role as Nini in HSMTMTS, writing original songs for the series. She debuted "The Rose Song" on the latest episode of her show Friday, following the singer's character as she goes through writer's block before coming up with a gorgeous track about "breaking through the glass you put me in."

"I'm really proud of it. I think it's really fun to write from the perspective of somebody that is not you," she told PEOPLE of the process. "It's really fun to write for characters. It's a fun, creative challenge for me. I always try to integrate my personal experience, and also my unique songwriting voices for the songs that I do for the show."

Like her Disney+ character, Rodrigo said she's felt the pain of writer's block through her own career, finding strength in pushing through.

"I think for me though, I just find writer's block as not being able to write anything that I like. I think everyone can always write songs," Rodrigo said. "They just think they're not always good. And so, I like to tell myself that sometimes you got to get the bad songs out before the good ones come."