Because your life only goes down from here.
21 is the most exciting birthday, but no one ever mentions what goes on after. Think about it- there is no more excitement in finally breaking through those darn age restrictions that have been haunting you your whole life. But that doesn't mean there is nothing to look forward to! Here is a very slim list of important birthdays you can look forward to after the big 2-1. (Beware: this list is depressing and will not make you feel any better about how old you're getting)
Age 22: You get to sing along to 22 by Taylor Swift and feel right about it because now you genuinely are feeling 22.
Age 25: You can legally drive a rental car.
Age 26: You get kicked off your parents insurance plan. If you haven't already, it's time to find a real job that provides employee benefits.
Age 28: You get kicked off your parents country club membership...so yea, your life is pretty much over.
Age 30: Your youth is actually over.
Age 50: Over the hill... yay.
Age 65: You get to retire, move to Florida, and sit on your a** all day. You also get $2 off at movie theaters with your senior discount!
80. Countdown to death begins because now you are old af.