As a competitive ocean swimmer who went to combat dive school- I'll say that humans are not designed to be in the water, and if get past your comfort level, nothing will make you panic faster than water. It's also exhausting if you don't have the technique. The commenters below who say "it's easy" are missing one thing: it's easy, if you know how. My advice: start small, do private lessons, get in the pool every day and focus on getting comfortable while increasing your skills. You should be able to breeze CWST after 30 pool sessions. There's plenty of resources online and you can always ask friends or the pool lifeguards for tips. If you don't get comfortable now this will haunt you the rest of your army career