This morning, I was both delighted and chagrined to read an article by Leah Rozen on nytimes.com about her decision to let her hair go gray. Delighted because I knew Leah as a freshman reporter on The Daily Collegian when I was a senior; chagrined because this post, which covers much the same ground, has been sitting in the computer of The New York Times since March 15. Leah and I were, of course working independently, with no way of knowing what the other was doing and thus no possibility of plagiarism on either side.

I lost it at the movies — my youth, that is.

The first time was a few years ago, when I handed over the Clearview Cinemas gift card I’d been given for my birthday. It came back with an odd balance remaining, $41 out of the original $50; I shrugged, figuring gift card holders must qualify for some special discount. More recently, I handed a $20 bill to the ticket-seller at the AMC Loews Lincoln Square. “Do you have 50 cents?” she asked. I looked at the register: $10.50. For a first-run film in Manhattan on a Saturday afternoon during Christmas season?

It’s happened at the pool, too. “Ten, please,” I asked the young woman behind the glass one day last fall, pushing $20 though the slot. She printed out my tickets and pushed them back, along with an unexpected $10 in change.

By now, I’ve realized there’s only one possible explanation: senior discount. The problem is, I’m not a senior. Whether the cutoff is the standard 65, the more generous 62 or even 60, I still have a few years to go.

We boomers have gone from being desperate to look older to looking older than we ever dreamed possible, from being the don’t-trust-anyone-over-30 generation to the we-can-fool-anyone-under-30 generation. It’s not necessarily their fault; young people think everyone older is old, and we all go through life assuming our generation is the baseline. Who’s more guilty of that than boomers?

There’s an invisible, perhaps imaginary line between young and old. It’s not like the way a woman immediately becomes invisible on her 50th birthday. (My friend Lois, nine years older than I, warned me about that, and I laughed. When the day came, I found out, quickly and painfully, that she was right.) Maybe it’s not so much a line as a gray zone, a period of years over which we gradually shift from one side of the divide to the other.

My personal gray zone — my hair — may be one reason for mistaken generational identity. About 10 years ago, I deferred to nature and stopped coloring it. The auburn I’d been sporting for 15 years yielded to brown-going-on-gray, a shade my hairdresser diplomatically termed “ash brown.” If questioned, I say, “I’m going for the aging-hippie look.”

The occasional bit of age discrimination, especially in hiring, aside, it’s paid off. Recently a colleague was talking about feeling depressed when she was offered seats on the bus or subway. “Do I look that old?” she moaned. I smiled. I used to be given seats because people apparently thought I was pregnant. (I’ve been genetically pear-shaped since I was 8.) Now I get them because of my hair. My herniated disk, acquired at 17, isn’t vain; it’ll take any seat it can get.

Not that my hair did me any good the time I ordered a bloody mary at a bar in Tampa International Airport — and was carded for the first time in decades. “We have to see proof of age from everybody,” the waiter, in his early 20s, explained sheepishly. I leaned forward and pointed to my roots, but that wasn’t good enough. A Manhattanite whose last driver’s license expired sometime in the early 1990s, I was flummoxed — until I realized that of course I was carrying my passport.

It’s a little disconcerting to realize how closely I’ve been following the politics of Social Security and Medicare this past year. And although I’m not yet old enough to borrow back the “Where’s my senior citizen discount?” T-shirt I gave a friend when she turned 65, I’m already looking forward to the discounts. Top of the list, especially as fares keep rising and service keeps declining: the MTA’s half-price senior Metrocard.

AARP defines itself on its website as “a nonprofit, nonpartisan organization for people age 50 and over.” But a friend of a friend, who spoke on condition of anonymity for fear of being blacklisted when the time comes, joined when he was about 25 after receiving an invitation when his father turned 50. “They asked for a birthdate, and I gave them my own,” he said, but he got the card anyway. “People would say, ‘You’re not old!’ I’d say, “I don’t care. I want the discount.’ ” (He’s no longer a member.) And here I’ve been tossing out the AARP membership offers that have been landing in my mailbox since I turned 50, on the grounds that I’m nowhere near retired — i.e., that old. (David L. Allen, AARP’s senior manager for media relations, anyone under 50 may join as an associate member and receive the publications, but no card or discounts)

I did, however, accept the offer from Smithsonian Senior Discount Services of a year’s subscription for just $10. (The newsstand price would be $65.89, though on Smithsonian’s website the regular subscription price is just $12.) A customer service agent, asked about the cutoff, polled her office and said no one knew of a specific age. She suggested that Smithsonian might have obtained my information from the database of another organization — most likely AARP.

These kinds of early-bird specials raise ethical questions of passively accepting discounts to which you’re not strictly entitled. Buying movie tickets at a machine in the lobby or online, I would never press “senior.” Nor did I lie to the pool manager, the one who knows which end is up, the time he was selling tickets and said, “I apologize for asking, ma’am, but are you a senior?” At least he asked. When someone looks at me and simply assumes, I tend to smile sweetly and let the employer’s profits take the hit — small punishment for no doubt denting egos less resilient than mine.

All I know for sure is, I’m never coloring my hair again.