I learned how to stay afloat in water from a pretty young age, since my family took trips to the beach every summer and eventually moved there. I wouldn't call my technique swimming, exactly, since I never strayed out farther than waist-deep in the ocean. Even the backyard pool we erected a few summers in a row was just three feet deep, plenty shallow enough for me to stand with my feet planted firmly on the bottom and my head safely above the water.
When I was in third grade, a few years before I began homeschooling, I had to take swimming lessons as part of my school's curriculum. It was the dead of winter and we had to travel on a bus to the local community center, since none of the town's three schools had a swimming pool of their own. At the start of the first session my gym teacher (a man I was none too fond of) told each of us in turn to get in the pool and swim. I told him I didn't know how, and he insisted that I try to flounder my was across the shallow end of the pool anyway. Needless to say, when the class was split up into two groups according to skill level, I was placed in the less skilled group.
An instructor from the community center took over my group, and eventually I learned to paddle around fairly well. I never did enjoy swimming in the deep end, though, and I particularly hated when we began diving. The diving board was only a little bit above the pool's surface, but I couldn't stand that awful moment between plunging in and fighting my way to the surface. Even just floating in the deep end was uncomfortable for me--the pressure of the water around my chest seemed greater somehow, and I was uneasy without the comforting presence of the pool's floor under my feet.
I haven't been swimming in years, but assuming that learning to swim works on the same principle as learning to ride a bicycle, I suppose I'll be all right!