I want to open water swim but I’m terrified

I did my first sprint tri but the swim portion was in a pool. I want to do more but they’re mostly open water and in NJ that means ocean.

I was really afraid of going in the water as a kid but I managed to overcome that and by the time I was a teen I was on the swim team. But I am still petrified of water where I can’t see the bottom. Any advice?