1. You're losing the hair on your head...
2. And "finding" it on your ears and eyebrows.
3. Speaking of hair, you're noticing more and more gray ones. Not enough to get your hair dyed, but enough to make you worry about when (or if) you should.
4. You recently realized that — for the first time in your life — you're older than almost every major league baseball player.
5. Most doctors look like this to you now:
6. You no longer throw your back out by playing football, but by passing the potatoes.
7. Even if you're not a dad, you suddenly can't stop yourself from making groan-tastic puns and dad jokes.
8. You are not amused by all of the '90s parties, which basically ask people to show up like you dressed in high school.
9. If you get carded, it's with a sheepish, "Sorry about this, sir. We have to card everyone. We'd card you if you were 80."
10. Your doctor gave you "the talk." This talk isn't about sex, but how you need to be healthier as you age. Sigh.
11. When you're looking for something to watch on TV, you usually end up re-watching, say, Back to the Future or Friday instead of any of the hot new shows.
12. You no longer recognize — or understand — the moves people make on the dance floor.
13. Your waist has likely expanded, but if it hasn't, people are really amazed by this fact.
14. When you try to eat as much as you used to, it SETS. YOU. BACK.
15. You've started to refer to people in their 20s as "kids."
16. Also, all of the musicians you loved growing up are being inducted into the Rock and Roll Hall of Fame.
Musicians are only eligible 25 years after their first album is released. So, yeah, I guess 25 years have passed since you first jammed out to them. Yikes!