Might just have been the day when I grew up - or thought I did.
It was, you see, the day on which my house-master came into the school library, where I was determinedly revising for my first A level, to be sat 2 days later, and told me that my father had died.
In common with many another only child, the death of my parents was the substance of, quite literally, my worst nightmares - and suddenly, here I was living it. But God is kind, and this, like so many other imagined fears, was less cataclysmic in reality than my dawn terrors.
The protective wall that had surrounded me through childhood was, in a moment, blasted away, but the world beyond was both gentler and more welcoming than I had dared to believe.
It contained music and poetry that would give meaning even in this situation of apparent chaos, where the certainties of life had been obscured.
It seemed I might not sink without trace, might even eventually enjoy learning to float.
That I was even half-ready to try is, of course, thanks to the unconditional love that my parents had lavished on me for so long that I never, for a moment, doubted that in this universe the facts are kind.
What's more, they bequeathed to me a language that enabled me to interpret what was happening when, as I travelled home by train to confront this life changed utterly, I was met in a railway carriage by a love beyond anything I could ever have conceived.
So 17th June is a day when, for all my concern for inclusive language, my thoughts will always be full of Fatherhood. It's the day when it seemed to me that, as one father's love was interrupted, I experienced Another's in ways I'd not dreamed of, a day to give thanks to one Father for the other.
Thirty one years on, I still do.