@helkel I have a pool in my backyard and still didn’t put my children into swimming until they’re closer to 3. They have exposure to water at bath time, I let the water pour over their faces when rinsing their hair and we blow bubbles in the bath water for fun. It’s only taken my girls one year from age 3-4 to learn to swim, “Life saving swimming” If they fell into a pool they could get to a side safely.
My oldest is now 7 and learning strokes and diving, underwater breath hold etc.
As for chlorine, It destroyed their hair so I invested in a good quality shampoo, conditioner and treatments for after swimming lessons. I also noticed they would get a runny poo (Sorry if TMI) occasionally if they accidentally swallowed some chlorine water.