Kim, Khloé, and Kourtney are sharing their reactions to Mason Disick joining social media and giving fans a glimpse of his life on Instagram.Kim Kardashian might soon qualify to have her star on the Hollywood Walk of FameKim and Khloé Kardashian react to Caitlyn Jenner’s comments: ‘It hurts me too’Bianca Censori reunites with her parents in Australia: Kanye West did not show up“I still can’t believe Mason is on IG,” Kim wrote, inviting her followers to follow him. “I can’t believe this is happening,” Khloé Kardashian commented, adding, “You’re really on Instagram.” The famous sisters are feeling nostalgic, as Mason is growing up.