On January 3, Iris Kessler's older sister Olivia gave birth to a beautiful baby girl.
Iris shared the exciting news with her friends and family on Twitter.
While Iris waited with her family at the hospital to meet baby Carter, her 18-year-old brother Grant turned up in clothes he thought were fitting for the occasion – because "first impressions matter."
People really appreciated the effort Grant put in before meeting his niece, and Iris’s tweet has been retweeted more than 400,000 times.
Iris said the world's reaction to the tweet has been "insane", and that Grant is trying to stay cool about it. "But I can tell he's kind of freaking out inside," she said. "It’s pretty adorable."