The old people are the ones that are about 10 years ahead of you. See how this works? If you are 20, those 30 year-olds are “old”. If you are 30, the 40 year-olds are “old”. And if you are 40, them 50 year-olds are “old”.
You’re not really old until your high school reunions start coming at odd intervals, and they start combining a few classes so they can get a dozen or so people together.
Next year will be my 30th, and I don’t know where the time went. When I was little and heard that people lived to be seventy years old I wondered what they did to fill up all that time. Now I think “It’s not enough, dammit!”