I know its safe, I know it feels great but I'm almost 30 and when I try to swim in a lake or the ocean where I don't see whats on the gorund arghhh. I'm afraid of it.

I have the same problem in the ocean. I have done many times scuba diving, then its not a problem because I can go down and see and I'm not alone, but being on the surface swimming grrr.....

Any advise? Am I stupid?