We asked members of the BuzzFeed Community to tell us the moment that made them feel old and their responses — along with some of the readers' comments — were hilarious and cringingly relatable:
1. "When I got carded at the grocery store and the clerk looked at my birthdate and declared, 'You were born the same year as my mom!'"
2. "When I was explaining to a high schooler how to dial a code and then the pound sign, and she asked me, 'Is that...like...the hashtag?'"
3. "I was working retail with some teenagers who were talking about Facebook, and one of them stopped mid-sentence and asked me, 'Wait, do you know what social media is? Do people your age use that?' I'm 30."
4. "My 10-year-old students asked me what songs Michael Jackson sang. When I answered, 'Thriller,' they asked, 'You mean the Party City commercial anthem?'"
5. "When my nieces looked at me like I was insane when I tapped my wrist to ask for the time."
6. "I was working at a high school blood drive, and the math team came in, so I threw out the quote, 'The limit does not exist!' They all stared at me."
7. "The time I asked one guy if he knew who Paul McCartney was, and he asked me if that's Jesse McCartney's dad."
8. "When I agreed with the adults at a bar mitzvah that the music was too loud and that it was too dark."
9. "I had to teach a 12-year-old how to use a landline phone, and when she was done, she handed me the phone, saying she didn't see the hang-up button."
10. "When I threw out my back brushing butter onto puff pastry."
11. "I'd started working at a college and was pumped to see some cute football players on campus. Then they arrived and looked like children, and I realized I could technically be their mother."
12. "The kids at the camp I worked at asked me what a cassette was, then were disappointed it couldn't play music by itself."
13. "The moment you see the doctor and wonder if they are old enough to be qualified."
14. "When my daughter asked me if I used to only see in black and white."
15. "One of my students asked me if I had ever seen the movie Men in Black because 'Jaden Smith's dad' was in it."
16. "When I showed my 4-year-old how to do a somersault and felt dizzy and nauseated for the rest of the day."
17. "When the teenager at Chick-Fil-A called me 'ma'am.'"
18. "When I had to explain to my son what a CD was. He couldn't understand why all the songs were Taylor Swift."
19. "Remembering the 100th episode of The Simpsons when it aired – then catching the 600th."
20. "When I realized Titanic was released 20 freaking years ago, and I vividly remember going to see it with my high school classmates the day it was released."
21. "I'm nine years older than my fiance´, so naturally my girlfriends started calling me 'Mrs. Robinson.' He didn't even understand the reference."
Some responses have been edited for length and clarity.