A 5th grader has no business entertaining her friend’s 2-year-old sister at a sleepover.

When you become a full-fledged adult, you finally feel like you’re able to be friends with people who are significantly older or younger than you. 26-year-olds can easily connect with 32-year-olds and don’t dwell on the fact that they were in 7th grade when their friend was a freshman in college. Once you’re at a similar stage of life as someone else, you don’t have to be so hung up on exact ages because it’s less relevant.

There’s a reason kids are so much less willing to spend time with someone significantly younger or older than them. The difference between a 6-year-old and a 12-year-old is far greater than the difference between a 26-year-old and a 32-year-old. Young kids play and relate to each other in ways that bore tweens, and vice versa. They like to engage with their imaginations, coming up with far-fetched scenarios to act out with their friends and similarly aged siblings. Anyone who knows tweens knows that they have long graduated from the «Let’s pretend I’m the mom and you’re my baby» phase of playing. Tweens want to engage with and relate to their peers, and they feel like they’ll fall behind socially if they spend all of their social time playing with their much younger siblings. Tweens can’t talk to their younger siblings about their crushes or their struggles at school in a way that matters to either party. They can always tell their 2-year-old sister about their gripes about mom nagging them, but if she can’t respond, complaining to her does little to build their relationship.