Celebrity Parents Kim Kardashian Shares Rare Photo of Mason Disick on His 13th Birthday — and He's All Grown Up! Kim Kardashian admitted that her nephew is "taller" as she shared a rare look at the teen By Angela Andaloro Angela Andaloro Twitter Angela Andaloro is a Parents News Writer at PEOPLE. Angela has also written about entertainment and parenting at LittleThings, Mom.com, BuzzFeed, and more. In her spare time, she enjoys competing in fantasy sports leagues and watching too much reality TV. People Editorial Guidelines Published on December 15, 2022 01:16 PM Share Tweet Pin Email Trending Videos Photo: Uri Schanker/Getty Images; Kim Kardashian Instagram Kim Kardashian is getting emotional about her nephew growing up. The SKIMS founder, 42, shared a heartfelt birthday tribute to nephew Mason Disick — the eldest child of Kourtney Kardashian's three kids and of all the Kardashian-Jenner grandchildren — on her Instagram Story Wednesday as he celebrated his 13th birthday. "The day has come where you're taller then me now," the proud aunt wrote. "I just love who you are and I'm just so proud of you Mason. Welcome to your teenage years 🤍 Happy birthday." The photo shows aunt and nephew back to back, separated a bit by both their backpacks. Mason has shaggy hair and wears sunglasses, a white t-shirt and gray sweatpants in the laid-back photo. 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. Kim Kardashian Instagram Mason wasn't the only one of Kourtney and Scott Disick's kids celebrating a birthday on Dec. 14. The teen shares his birthday with little brother Reign, who turned 8. The former couple also shares daughter Penelope, 10. Last year, Kim praised her nephew over a text exchange regarding her daughter North West's online safety after the then-8-year-old went live on TikTok without permission. In screenshots posted to Kardashian's Instagram Story, Mason suggested that North be supervised when filming content for social media. "Hi I don't wanna disrespect north but I don't think she should do the lives unless someone is with her because people are always screen recording and she might tell information that isn't correct and stuff like that, that she will regret," Mason told his aunt. "I did the exact same thing as she did. I would do the lives and now I regret saying one of the things that I said," he continued, adding, "Just in case for safety." Kourtney Kardashian Says Sons' Shared Birthday Is 'One of the Best Days of My Life' Courtesy Kim Kardashian Praising Mason's actions, Kardashian wrote: "Now Mason is so mature! An insightful king" over the screen grab. In a second slide posted to her Instagram Story, Kardashian shared her response to her nephew. "I appreciate you looking out Mason And I agree. She felt bad and I don't think she will do it again but it could be good if you talk to her about it," the SKIMS founder replied. Mason agreed, telling Kardashian he would "love" to chat with North, and the reality star then suggested he "sleep over soon."