Good Luck Charlie alum Mia Talerico headed off to her first day of senior year and reflected on how time has quickly flown by.

In pictures shared to Instagram Aug. 19, Talerico sported a pink, shoulder-free top and jean shorts as she posed with a sign that marked the momentous occasion.

“Last First Day!” the 17-year-old wrote in the caption. “Now I'm starting to feel old.”

And it’s not just the Disney Channel star who is shocked by how far she has come. Indeed, Talerico’s annual tradition of celebrating her first day of school has stunned fans who watched her on TV as a toddler.

"That’s so crazyyy we literally all [watched] her grow up," one fan commented on last year’s post. Another added, "This is really the same charlie i grew up watching. im 22 now."

Of course, Talerico—who starred in Good Luck Charlie as the titular role of Charlie Duncan from 2010 to 2014 alongside Bridgit Mendler and Bradley Steven Perry—is aware of how odd it is that she has aged in front of everyone’s eyes. 

"It’s so weird," she said during a Destination D23 event last August. "So many people know who I am, but I don’t know them. I think that’s a really surreal feeling."

"People still come up to me and ask me about it," the teen added. "I think sometimes it’s a little funny because obviously I was so little, so I look so different, but it’s awesome to see that people still love it.” 

And Talerico is grateful for fans’ memories, because she confessed she doesn’t have too many of her own.

"Obviously, I was so young that I barely remember a lot of it," she admitted. "But I’ve heard so many stories and watching it back is truly like a family scrapbook."

For more stars who have celebrated the beginning of the new school year, keep reading
 

The singer made sure to soak up the sun with her son Wyatt before sending him off to his freshman year of college.

"Where does the time go?" whe wrote in an Aug. 17 Instagram post. "For any parent who just went through this, I know how you are feeling! So proud of the young man he has become, and sure am missing him around here!"

On Aug. 13, the Oscar nominee and her ex Iman Shumpert celebrated their daughters Junie Shumpert and Rue Shumpert's "first day" while showing there's one resemblance after another between the actress and her kids.

The Food Network star reunited with her ex Todd Thompson on Aug. 8 at a college send-off party for their daughter Jade.

The NBA star escorted his son Prince—who he shares with ex Jordan Craig—to his first day of fourth grade, joking in an Aug. 12 Instagram, "Man I’m getting old."

The Sabrina the Teenage Witch alum enchanted to see her and husband Mark Wilkerson's sons Braydon and Tucker head back to school on Aug. 12.

"Last first day of school for our Brady," she wrote on Instagram. "Senior year for him and 7th grade for Tucker. May God bless and protect all the children as they head back to school!"

Matthew Stafford's wife snapped this photo of the NFL quarterback sending their twins Chandler and Sawyer off to their first day of fourth grade. As she captioned the photo on Instagram Aug. 12, "New school, same girls."

The former Dancing With the Stars pro waltzed her and husband Sam Cusick's daughters Sage and June to class on Aug. 12, writing on her Instagram Story, “I can’t believe they are both starting school now.”

Summer is winding down. The Whine Down podcaster sent her kids Jolie and Jace—who she shares with ex Mike Caussin—as well as her and husband Allan Russell's son Roman off to their first day of school on Aug. 10.

"First day of Pre-K3, 5th grade & 2nd grade," she captioned a photo of their blended family. "So proud of these three and excited for all this school year will bring."

Jason Aldean's wife shared photos of their kids Navy and Memphis heading back to school on Aug. 11, calling it an "emotional Tuesday."

She's going to school for all the right reasons. The Bachelorette alum saw her daughter Addison start seventh grade on Aug. 11.

"You are incredible Tiny," she wrote on Instagram. "Praying for a great year in middle school!"

The Ex on the Beach alum helped her and Cory Wharton's oldest daughter Mila get ready for elementary school. As she wrote on Instagram Aug. 12, "My little first grader."