I was swimming with my kids and some of my grand babies under water before they were a year old. They naturally hold their breath and have no fear. Fear is a learned reaction.
I totally agree with you.
She wears the life jacket when we are over at our friends because there is a steep drop from the shallows and depending upon the tide it can be hard to judge where it is. Especially for a little one. Also, the wakes from the boats coming through there can cause some hefty swells.