I had not worn white in thirty years, in case something spilled. Then I wore it to a lunch with a pavlova.

I should say first that I am not much of a writer. I am sixty years old, I keep a tidy house and a tidy bowls roster, and the last thing I wrote that was longer than a birthday card was a reference for my niece. But three women asked me about a dress at a lunch last month, and by the third I thought: if three women asked, there are plenty more wondering. So I had better put it down in one place.

It began about six weeks before that, in our bedroom. I was laying the navy dress out on the bed for yet another lunch, the same navy dress I have worn to every lunch, christening and funeral since about 1996, when Graham stopped in the doorway and said, quite kindly, "You know you have been dressing for a spill for thirty years."

I was cross for about a minute. Then I was cross because he was right.

Nobody decides to give up white. It happens in small steps. A glass of red at a wedding when you are thirty-five. A toddler with jam at forty. By fifty you have stopped buying it, and by sixty you are standing in a shop telling yourself that navy is "more practical", when what you actually mean is that you are tired of being careful.

And the shops do not help. Walk into most of them looking for something light and pretty for a summer lunch and you are offered beige, grey, or a black that is somehow meant to be festive. White, if it is there at all, is a shirt. A proper white dress with some life in it, for a woman my age, almost does not exist on the rack.

My sister Lorraine is sixty-three and the least reckless person I know. At the family barbecue in September she turned up in a white dress scattered with soft pink roses, and I watched her eat a sausage in bread, with tomato sauce, in it. Standing up. On the lawn. Without a flicker of worry on her face.

I asked where it was from before she had finished the sausage. "Sofia Wellington," she said, and told me I should have a look. I had ordered from them a few times by then, always a top or a blouse, and had never once clicked on the dresses, because I assumed there would be nothing in them for me. I went home and looked that night, and I had ordered the same dress by bedtime.

It is called the Barbara, and I will describe it, because I know you will want to know. It is white with soft pink and deeper pink watercolour roses scattered over it, with a V-neck, three-quarter sleeves and a gathered seam at the waist, and then a long, flowing maxi skirt. It has pockets in the sides, which I discovered in the first five minutes and have not stopped mentioning to anyone since. There are twenty-one other prints in the same shape if white is a step too far to begin with, and you can see them all here.

The Barbara had its first outing at Jan's seventieth birthday lunch, at the end of October, in her garden. A long table under the umbrella, about twenty of us, and a pavlova the size of a hatbox, with strawberries, cream and a jug of rosé going round. I stood at the end of that table in a white dress, and I will tell you plainly that my heart was going a little.

Nothing happened. That is the story. I ate the pavlova. I held a glass of rosé. I leaned over to hug three different people. And somewhere around the second helping of strawberries I realised I had stopped thinking about the dress entirely, which is the whole point of a dress.

What did happen is that three women came up to me before the end of the afternoon. Pat from the garden club said she had not seen me look so well in years. Jan's cousin from Hamilton asked where on earth I had found it. And Jan herself, who has known me since we were girls, took my arm and said, "Margaret, you look like yourself again." I did not know what she meant until I thought about it in the car, and then I did.

1. White is not the risk I thought it was. The roses are busy enough that a stray drop does not announce itself, and I stopped scanning the table for threats about ten minutes in. What I had really been afraid of was never the stain. It was the fuss.

2. The shape does the flattering for you. The V-neck opens the top, the gathered seam sits at the waist and the skirt falls loosely from there, so nothing clings and nothing needs holding in. The sleeves land at three-quarter length, which covers the part of the arm I like least without feeling heavy.

3. It goes anywhere. I wore it to the lunch with flat sandals and a little gold at my ears. The following weekend I wore it to the markets with a denim jacket over it. Dressed up or down, it did not seem to mind.

I will be plain about the price, because I was a little shocked by it. The Barbara is $89.95, down from $179.95, in the spring sale on at Sofia Wellington right now. At the full price I do not know that I would have taken the chance, because I did not know then what I know now. At under half, it is less than I have spent on dresses I wore once.

There is also the offer for ordering more than one: two dresses take 10% off the whole order, three take 15% and four take 20%, applied at checkout. I have read the reviews now too, 4.8 stars from more than nine thousand women, and a good many of them tell a story close to mine.

If we were sitting on my deck with a cup of tea, and you asked whether you should order one, this is what I would say.

I would tell you that women our age have been taught, very politely, to hide in dark colours, and that it is a habit rather than a rule. I would tell you the white is the one that gets noticed, but that there are twenty-one other prints in the same shape, and if white is too big a step, you could start with the cream or the sage.

I would tell you that with the Christmas lunches and summer parties coming, the sizes will not last. What is gone does not come back.

And I would tell you not to wait until the week before, when you are standing at the wardrobe looking at the navy again.

If you have been dressing for a spill, please order one now, while your size is still there.