Celebrity Celebrity Family Celebrity Babies Scott Disick Celebrates Son Mason, 14, Graduating Middle School: ‘My Best Friend in the World’ "Now on to high school," wrote 'The Kardashians' star on Instagram as he posed with his son outside Nobu By Gabrielle Rockson Gabrielle Rockson Gabrielle Rockson is a staff writer-reporter for PEOPLE. She joined PEOPLE in 2023 and covers entertainment and human interest stories. She's interviewed David Beckham, Zendaya, Timothée Chalamet and many others. Her previous work can be found in OK! Magazine, MyLondon, GRM Daily, and more. People Editorial Guidelines Published on June 7, 2024 08:04AM EDT Close Scott Disick with his son Mason and daughter Penelope; Scott Disick with his son Mason. Photo: Kim Kardashian/Instagram; scott disick/instagram Scott Disick is celebrating an important milestone in his eldest son’s life. On Thursday, June 6, Disick, 41, shared a congratulatory post to celebrate his son Mason Dash, 14, graduating from middle school. “Congratulations 2 my best friend in the world 🌎 for graduatiuating middle school and now on to high school! Let’s go mart!!,” the proud father wrote as he shared a photo that featured him standing in between Mason and a friend. In the snap, which appeared to be taken outside Nobu Malibu, Mason and his pal turned their backs to the camera as Disick rested his arms on their shoulders. Scott Disick Shares Blinged-Out Photo of Son Reign as He Wears Matching Cheetah Print Set Disick, who shares Mason, daughter Penelope Scotland, 11, and son Reign Aston, 9, with his ex Kourney Kardashian Barker, covered his eyes with a pair of black sunglasses as he wore a jacket over a dark gray T-shirt and cargo pants. Mason, meanwhile, sported a long-sleeved red T-shirt and baggy black pants. “How is he in high school already? I swear he was just born 😢,” one person commented, while another added, “Go Mase!!! It’s crazy how fast they grow up 🥹😭.” The PEOPLE Puzzler crossword is here! How quickly can you solve it? Play now! Scott Disick and his daughter Penelope. scott disick/instagram Scott Disick Enjoys Quality Time Getting Dinner and Riding Dirt Bikes with Son Reign: 'Funny Little Guy' That same day, Disick also shared a sweet new snap of his daughter Penelope on his Instagram Stories. “Love u peep,” the father of three wrote across the photo as he carried his little girl, who flashed a peace sign to the camera and pouted her lips. Disick's congratulations for Mason come after his eldest child joined Instagram last month. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. Mason’s debut photo featured him standing outdoors on a balcony with his head dipped down while sporting a cap. “I can’t believe this is happening,” his aunt Khloé Kardashian wrote, while his other aunt Kim Kardashian commented, “You’re really on Instagram 🥹.” His mother also added, “My first baby 🥹.” While Kourtney shares three children with Disick, she also welcomed son Rocky Thirteen with her husband Travis Barker in November 2023.