1. That you'll watch your sibling get away with crap you NEVER would have.
2. That you'll pass on your hand-me-downs and realize your sibling looks better in them.
3. That you'll go from being called "big sibling" to being called "OLDER sibling."
4. That you'll be asked "Aren't you ______'s older sister?"
5. That you'll notice your little sibling looks so much older now and this means you probably look like the Crypt Keeper.
6. That you'll ever, ever being mistaken for your younger sibling's parent.
7. ...Or your sibling's date.
8. That you'll see your younger sibling drink for the first time and it'll hit you that they're no longer 12 and gross.
9. That you'll reach an age where giving your little sibling a noogie makes you look insane.
10. That you'll notice something annoying your sibling does and realize they got it from YOU.
11. That your teeny little baby sibling will eventually go out and date a serial killer or something.
12. That questions like "Why can't you be more like your little sibling?" will never end.
13. That you'll be forced to give them rides everywhere until they're old enough to drive.
14. That they'll do something to thoroughly embarrass themselves on social media.
15. That their weird little friend who has a crush on you will never go away.
16. That you've been a bad influence.
17. That they won't take your wise advice.
18. ...Or that they don't even need it.
19. ...Or that you've emotionally scarred them somehow.
20. That your little sibling is actually far, far cooler than you'll ever be.
21. That they might never know how much you truly love them.
Go call your little sibling. Even if they're a booger head.