The trouble was my starting sentence came pretty close to the end of the chronological story, so much of it had to be done in flashback, and worse, flashbacks within flashback. (Shock horror! Yes, the woman on a mission to eradicate flashback from prose was once an offender.) It made it hard to follow what exactly was going on on the first couple of pages. I vaguely remember being aware of that, and trying to signpost exactly where the reader was in the story.
It never occurred to me to change where I'd started. And yet, why was I so wedded to that opening sentence? The first words of it weren't even mine. It was because my writing mind lacked flexibility. The story started there because that was where it had started in the writing class exercise and that was that.
First draft writing is about getting those initial ideas down. Re-writing is about being flexible. Why shouldn't this bit go there, rather than stay where it is? Does John have to be an engineer? Could John be Joanna? What if Rover the dog was a cat called Pushkin? What if we set this scene in a fish market instead of a tea shop? Does the story need John/Joanna at all?
We get hooked on the initial ideas and images that inspire us to write and become rigid when change is mentioned. But writers need to be flexible when it comes to looking at our work a second time. I like the opening line of my old short story. It's a good one. But it screws up the rest of the story telling and then I lacked the flexibility to change.
Now I try to write with as much flexibility as possible. Everything is up for change, depending on the demands of the story. I try to keep the writing as fluid as possible until the last moment, which means I have moments of despair as I survey the utter mess that is my novel. But I remember the fable about the sapling, that can bend with the storm, growing next to the mighty but rigid oak, that topples in the wind. Flexibility is good.