I am standing at the front door, locked out of my own house. If this were a movie, it’d be raining. Thankfully, this isn’t so it isn’t. But the reality is embarrassing enough without any Hollywood embellishments.

You see, we have this digital lock. To open it, you input a numeric code. We bought it months ago and I’ve been using it without incident. But now, standing out here in the dark, I am, suddenly and for no apparent reason, stuck. After a moment, with more hope than confidence, I punch in some numbers.

Some wrong numbers. Instead of the lock disengaging, the keypad displays an intimidating red “x.” I search my brain for the right numbers, but it’s locked tighter than the door. I can’t remember.

I find myself saying that a lot lately as I creep toward the 30th commemoration of my 30th birthday. Reminds me of an old expression: “Of all the things I’ve lost, I miss my mind the most.” Don’t know who said that. Maybe I once did but if so, I don’t remember. Indeed, the list of things I don’t remember is growing long.

There is, for instance, my employee ID number, necessary for filing expense reports and viewing pay stubs. (Yes, they pay me for this. I’m as surprised as you are.) But it’s not just numbers. The other day, I was telling this guy about taking my granddaughter to the circus. I’m going on and on about this stuff I bought her that’s fluffy and sugary and it comes in clouds of pink and blue and you eat too much and it makes you sick. Finally, mercifully, he says, “cotton candy?” A few weeks ago, I have to ask a colleague what’s that word for a person who receives money after the death of a family member. “Heir?” she says.

“Yeah,” I say to her.

“Duh,” I say to myself.

Numbers and words are bad enough. But I also walk into rooms for reasons I can’t recall, open browsers and can’t remember why.

As the author of a novel (“Before I Forget”) about a man with Alzheimer’s disease, I regard this warily. But somewhere in my research for that book, I ran across a doctor – forget his name – who said that if you have the presence of mind to wonder if you have the disease, you don’t have the disease. Alzheimer’s is not about forgetting where you laid the keys. It’s forgetting what keys are for.

But if I don’t have Alzheimer’s disease, it seems apparent that I do have Oldtimer’s disease, and an advanced case at that. OD won’t kill you, but it will frustrate you near about to death.

Thank goodness my mind is still a steel trap for the important stuff.

Sports? Magic Johnson is from Lansing, Mich., played his entire career for the Los Angeles Lakers, went to nine NBA Finals and won five.

Music? I can still nail Philllipe Wynne’s famous ad lib from the end of “Mighty Love” – every grunt, shout, stammer and howl.

Literature? Amazing Spider-Man No. 44 was “Where Crawls the Lizard” by Stan Lee and John Romita.

None of which helps me open my front door.

I stand out there longer than I should, punching in wrong numbers. Finally, with a sigh, I call Marilyn who’s inside, and explain my predicament, trying not to sound as sheepish as I feel. My wife gives me the code without comment, a small kindness for which I am grateful.

My hair is gone, my knees are gone and now my memory is a memory. Life, it seems, is just a voyage into decrepitude. Or at least, so I am grumbling to myself until I read where George H.W. Bush just marked his birthday by jumping out of an airplane – and he’s 90. Ninety! So maybe I should stop whining, and just write the lock code down. Because maybe what life really is is a thing to be seized, held tight and wrung dry every day that you have it.

I get that. No, seriously, I do. It’s just that, of all the things I’ve lost, I miss my mind the most.

(Wait … did I say that already?)

The author will be chatting with readers Wednesday from 1 to 2 p.m. on www.MiamiHerald.com.

Leonard Pitts is a columnist for The Miami Herald. He can be contacted at:

lpitts@miamiherald.com