I'm really surprised by this 🤔 but there we go!
OP, I couldn't swim. Like properly couldn't swim. I don't know if you've found the same, but when I used to tell people I couldn't swim they always assumed I meant just not very far or well or just lacked confidence. But I mean properly couldn't float and had never swum a stroke without a float.
I started lessons in July and can now most definitely swim ☺️ so I'd echo PPs who say to have lessons. I honestly would never have thought I'd be able to do it, so if I can then anyone can.