I think its like going down a very tall roller coaster. At first that second it starts it is a bit startling. First we tried it without my head in. That was much less scary. When I felt ready I went in head first =D
The very first time I tried it I freaked out. I recommend baby steps with this kind of thing. Its worth trying more than once even if you freaked out the first time.
Live life to the fullest & try anything once… or twice =)