It's mogul skiing to me

What makes you feel old?
[Answered on quora.com by Dushka Zapata]
Not that long ago, I was sleeping snug in my bed in my room in a town a few miles South of San Francisco when the phone began to ring.
It was early in the morning, maybe 7:00, and I was still sound asleep because I had stayed up late the night before.
It was my Dad.
“Dushka” he said. “Are you OK?”
Whah?
“Yes! I’m home. You woke me up! What’s going on?”
He sounded incoherent. My Dad was the most eloquent man I have ever known, so hearing him trip over his words alarmed me. I felt a sense of doom.
“Have you seen on TV what is going on?”
“Dad” I say again. “I was asleep”.
“Dad. What is happening?”
“I am watching on TV a spectacle Dante never imagined” he says. “A plane full of people just flew into one of the twin towers in New York City”.
I am recounting this horrific story to a woman who works in my office. “Wow,” she says. “So you remember everything.”
I look at her completely perplexed. “Of course I remember. I was in my early thirties”.
“Oh” she replies. “I was six”.

[N.B. from Anna: I was also the mother of a 6-year-old (and 2 others) when that event happened unto us.]