Not being able to swim 25m curtailed my activity choices for school camp and banned me from activities that sounded interesting. I was left a "choice" of 2 out of 6, one of which sounded chronically boring. The irony was that one that I really wanted to do (a gorge walk) required no swimming ability during the droughty low water levels, but no tick in the box still ruled it out.
I couldn't go swimming with friends because who wants to be left in the shallow zone while they had the whole pool and diving boards avaliable.
Later in life, if I hadn't learned to swim I'd have lost out on the only accessible exercise in hard pregnancies
I generally felt inadequate about not being able to do something "basic" that everyone else could do (along with not being able to ride a bike). At primary school there were 2 of us out of 60 that hadn't got the hang of it by the end of primary school lessons. DM didn't do swimming because it's a bit cold. (It also fed into the family narative that females are shit at sport before becoming frail and enduring 30 years of arthritis from 60 to 90)
Going to adult lessons at 16 was embarrassing- and the pensioners there didn't appreciate a whippersnapper splashing around, but when I progressed, it became empowering. 2 years later I could swim a mile.
I wanted better for my children, and especially as one of them turned out to be dyspraxic (wonder where that came from...), so it's been a long, slow time. DS1 isn't currently interested in swimming (grumpy teen) but at least he's got those skills and options and isn't held back by being unable. DS2 is doing Rookie Lifeguard for the fun of it.
At their age, I felt like not being able to swim was a shameful, limiting secret. What they do about swimming now is their choice, but at least they do now have options.
@TreeDudette asked if posters could swim strongly in adulthood, and I do. Having been a non-swimming teenager who couldn't go down the deep end, the diving boards, the water slides and didn't get the choiced on school trips, I appreciate the practical differences between being a non/ weak swimmer and a strong swimmer, and it was important to me that my DCs could do more than the minimal 25-50m. The mile is only relevant in that I can still do it regularly and have maintained my swimming ability. The great thing about swimming is that you retain the technique and as long as you're fit, the stamina comes back quickly after long breaks.