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One of the things that can be said about the social enthusiasm of college students is this: That is one infectious spirit.

In one of our “money” conversations this spring, I reported to our college junior that he was over budget and asked what was going on.

“Oh that,” he said, explaining that after it had snowed an inch on his North Carolina campus, the administration had “freaked out,” and cancelled classes and thus he and his friends threw a “snowpocalypse” party. A big one.

And so, he had to spend a little more on that.

I’ll bet all those morning commuters in North Carolina who slid into each other on the way to work didn’t throw a party.

Ah. Youth.

A week before this call, the question of “What makes us old?” had been posed in a writer group I belong to. Predictably, because most of us know we’re aging but bristle at the notion of becoming “old,” the comments were all over the place and ranged from defensive to silly.

The question of when we’re old is not troubling in my view. It is just unanswerable in my view, because it’s an issue of spirit more than years. I’ve known humorless 30-year-olds who are older than whimsical 60-year-olds. And while it’s hard to describe the difference between an old and a young spirit, it’s easy to observe if your millennials range in age from snowpocalypse to married-with-a-masters.

We’d risen at 4:30 a.m. to catch an early flight from Boston to North Carolina to visit our snowpocalypse-party-throwing son, wishing to spend as much of our arrival day with him as we could. We met him for lunch, and again for dinner, after which we assumed he would head to whatever-he-does, and we would head back to the hotel.

But our son was eager to introduce us to his buddies, and had already invited them. And so he asked us to come by around 10 p.m. for a couple of rounds of beer pong before their actual party started at midnight.

“I mean,” he said, quickly, “we’ll use water. You don’t have to actually have beer.”

Beer or water, this could not have been less like whatever-we-do, and I was sure he was being polite. We might have passed, we almost did.

“We’ll be there,” I said.

We went.

We stayed.

We played.

The guys cheered when my husband got the ball in the cup, there was high-fiving when he and our son won, there was another round, and when I started asking questions about this and that, and then asked, “Can I try?” five guys jumped in to advise me to “float, not toss” the little ball, use more wrist than arm, and so on.

Well in advance of being wished away, and certainly before actual party-goers arrived, we left.

“It was so awesome that you came by,” said our son, walking us to the car. I was sure he wasn’t just being polite.

The experience of hanging out with our son and his respectable (and authentic – not one of them felt any need to dial down their language in our presence) friends left us feeling lighter for having shed the parent cloak for a brief time. But mostly, having been asked and welcomed into our son’s “other world,” left us feeling spontaneous and happy – all things youthful.

On the plane, I thought more about that “What’s old?” question. Here’s what I learned:

Old is taking part in something that might be fun only if it’s easy.

Young is taking part in something that will probably be fun even if it’s hard.

Old is looking back on everything that’s already happened as better.

Young is looking forward to what will be even better

Old is cautious.

Young is energetic.

Old cancels classes.

Young has a snowpocalypse party.

But above all, I learned at college this year that we aren’t old if we are simply no longer young. We’re old when we feel we’ve seen the best of life already and don’t bother to look further. We’re old when we say, “Thanks, I’d rather not.”

Age is a required course. But old is an elective. And so my plans to act my age include never refusing an invitation to view our children’s lives up close, and, possibly, throw a nice wine-pong party for my not-old-either friends.

Susan Bonifant is an essayist, novelist and mother of four who blogs about life after the last college drop off at Attic View. She lives with her husband and writer cat in Hopkinton, NH.

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