"Once you have kids, you don't care."
I wouldn't have minded but afterwards, when she put her hands behind her head to towel dry her hair, she nearly had my eye out.
I do care. I can't be the only one who hates changing rooms. Bodies of every shape and size go on display as parents nonchalantly spray themselves with perfume or slap on moisturising cream.
All the time I was screaming inside: "This is supposed to be a party!"
As party invitations reach me for my children, I'm generally delighted and thankful they've been asked to go and have a good time with their friends.
When the celebration involves swimwear – and I mean mine – I'm suddenly not so keen.
Thankfully I'm not needed these days if my girls, now 13, are invited to a swimming party.
But memories of accompanying them still make me shudder. It was stressful enough keeping an eye on both of them in a swimming pool on a normal day – add a gaggle of over excited friends splashing about to the mix and it's a recipe for a migraine.
My friend Katie, mum to Ben, nine, experienced such an ordeal just a week ago and hasn't shut up about it since. For her, it was the other mums, strutting their stuff in the pool that brought on her unease.
"I hate getting in the pool with all the other parents, I don't want to flash my body at people I see on the school playground every day," she says.
"Some people seem to love it though, It's funny the smaller their swimming costume, the more they like it.
"Also, I'm not a huge fan of parties where I feel I have to stay – I prefer it when Ben can be at a party without me or his dad, with his friends and the adults running the party. I hope it's not too terrible to admit I relish the hour or so for a bit of me time.
Swimming parties are the opposite – not only do you have to stay, you also have to strip off. How awful is that?"
Swimming party food is also an issue for me – and for Katie.
She says: "You can guarantee you'll be stood there in a freezing cold hall with a stale cheese sarnie – no thank you."
My friend Helen, mum to Ellie, nine and Rhona, six, pours cold water on our scorn for such parties.
She says: "We've been to some wonderful swimming parties with fantastic inflatables, staff who have been willing to join in the fun and really good facilities.
"When I've gone, it has mainly been dads who get into the pool with the kids and it has made a nice change for them to be involved in a party in this way.
"Food has never been a problem, we've been able to take our own to keep costs down. All in all, I can't see what there is to moan about."
Helen raises a good point about cost (even if we disagree) - for me it's extortionate. I was once convinced it was a good idea to look into a swimming party for my girls and nearly keeled over when I was told how much it was for each child.
With prices in our area currently quoted at around £9 per head, plus an extra £2.50 each if you want to take up an offer of a specially-designed invitation, I'd prefer to dive in to a bit of home-made fun instead.
It may be messy. But at least everyone can remain fully clothed.
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