It's 99 years gone since my great-grandad Corporal Grade, a professional soldier of nearly 10 years' standing, shipped out for the 'big show' over in Flanders, so today I decide to don the poppy for the first time ever in the school.
Don't get me wrong – it's not that I haven't worn one before because of any kind of political reason – I just wasn't bothered, but with the centenary coming up, you know . . .
Plus, I do know my history and I know that our oul' lad signed up because he couldn't get a job at home.
Regular pay thrown in with a good chance of some serious heart-stopping action looked better than dying of TB in a tenement or on the ghastly family farm. Just like being a teacher and walking into my school wearing the poppy, actually.
First reaction of the day: history teacher, Mr Prince, scion of an Old IRA family who is probably the first of his generation to escape some ghastly farm perched high on a cliff on the Western Seaboard, can't contain himself.
"Now I've seen it all! It's Grade proudly wearing a symbol of British imperialism."
I come right back with, "Shut up, you lost the Civil War. Get over it!" and retreat.
Next it's Róin Shine, who teaches Irish, in that half-world called the 'corridor'. He peers at the black and red flower and chuckles: "Red and black badgey-thing? You supporting Man Utd now?"
Humour. Things are looking up.
Onwards to cover fifth year, whose French teacher is out ill.
As soon as I enter the room they're at it with, "What's the badge for Sir?" I explain that it's to commemorate all the Irish soldiers who fought in the British Army in World War One.
I brutally suppress a notion that that was the one with Rambo in the 1970s that broke for a few years until Hitler got out of prison.
I recognise it's not their fault that they weren't given the option of taking history for the Leaving. Someone says, "I hate that Hitler fellah", so they do know something.
No, I answer, you didn't have to have LC honours in French to go over, strange as it might seem these days, all you had to was turn up, fight and try and survive somehow.
Explaining trench combat, progressing to the massive artillery battles and how the US tipped the balance at the end, I decide to round it off with the story of my great-grandad.
No, he didn't die in the War. I pause. It occurs to me that I don't think he did actually fight. I now find myself scratching my head, trying to remember the story.
Suddenly I'm going red in the face as it all comes back; he fell off the ship, caught pneumonia and tended a store room on the Curragh for the next four years– hardly the stuff of glory.
"Ehm," I say (come on bell, ring). "I'll tell you about him tomorrow." But only if that French teacher doesn't recover first.