1.This girl, who is the authority on what is officially "old age": 25.
2.This person, who a) thinks that your twenties last for "a couple" decades, and b) is letting you know you're not allowed to be "young at heart" past the age of 29.
3.These kids, who are blown away by the concept that 25 is the same as one quarter of a century.
4.These people, who understand that as soon as women turn 30, life is all downhill.
5.This Tumblr user, who is terrified of the inevitable onslaught of wrinkles one gets at 21.
6.This person, who is aging quite gracefully.
7.This Twitter user, who is NO LONGER A TEENAGER OMG.
8.This pesky 20-year-old.
9.This 18-year-old who clearly doesn't understand that truly old people do not count down their birthdays two months out.
10.This person who thinks 23: #SoOld, #Cougar.
11.This person, who is one step from the grave.
12.This person, who is...a ripe old 25?
13.This lady, who has the best life ever, but doesn't even realize it.
14.This person, who can currently be found in the nearest restroom.
15.This person, who just found her first gray hair and is about to have Miller Time.