It's that sinking feeling when music seems too loud, getting out of bed in the morning takes a little more effort, and the world appears to be full of teenagers.
You never imagined that time would come when so many people seem younger, but now you're entertaining the question: Am I old?
An interactive graphic by Nathan Yau of FlowingData, a blog that explores statistics, analysis and data, allows you to see how old you are compared to the rest of the U.S. population, based on the five-year American Community Survey estimates from 2014. The graphic shows that right around 37 or 38 is when there are more Americans younger than an individual instead of older.
However, there is a big difference between being "old" on paper and feeling old, according to an expert.
"It's very much a cultural and societal thing,'' Andy Scharlach, the director of the Center for the Advanced Study of Aging Services at the University of California, Berkeley, told TODAY.
"It depends on what standard we want to use. Most 37-year-olds, unless they're really disadvantaged in terms of their situation or working a hard labor job, feel pretty darn young and don't feel that different from their 20s. It's not really until people get to be 60 or older that they really feel their age."
It's not like people in their 60s are despairing about their age in a significant way, either.
"If you ask people about life satisfaction and quality of life, people in their 60s or 70s actually have the highest ratings of life satisfaction,'' Scharlach said. "It's high in your 20s, then goes down, and comes back up in people's 60s and 70s."
For any 37- or 38-year-old American depressed over officially being older than the majority of the country, there is a silver lining.
"The U.S. is one of the younger countries in the world," Scharlach said. "You look at countries like Japan, Germany, Italy and pretty much all of Europe, and they're all older than the U.S., so that age wouldn't make you older than the general population."
Follow TODAY.com writer Scott Stump on Twitter.