Most digital cameras have a small delay between pressing the shutter button and the actual shot being taken, although your time seems a little long.
It's very disconserting for those of us who have been used to film cameras for many years, especially the between lens shutter types, which operate virtually instantaneously.
Such delays can mean the difference between getting, for instance, that facial expression you thought you were capturing and missing it altogether.
Another reason could be that you have the camera set to prevent red eye - an initial sequence of flashes are rapidly set off before the actual picture is taken.
Funny thing red eye - my Minolta Dimage E203 manages to produce it even virtually side on to the subject if flash is used.
Yet shots with a Nikon SLR with the flash held a couple of feet away from the camera are usually red eye free...