-- Last Updated: Dec-10-12 12:15 PM EST --
We can't decide for you, only provide advice.
I actually ran experiments, with various clothing on.
Waded into the water till I was floating,
hung around a few minutes, then returned to my apartment.
My neighbors thought I was crazy, they were right :-)
One neighbor insisted I tether myself to a tree,
so I tied two throw bags together for 100 ft of line.
It's damn tough to swim the first 30 seconds
when all muscles clench the body into fetal position
in an attempt to preserve heat at the core.
Dunking head under water - filling that wetsuit full -
not fun at all, the first few seconds, but it can be done.
Wind whipping over a wet body as you get out
can be a huge kick-in-the-rear as well.
A simple cheap digital fever thermometer can easily
show you if that core temp dropped a few tenths of a degree.
Fear can be overcome by understanding and learning.
Controlling fear/panic is crucial to survival.