Well the only way to know is try! From the point when they take you, they can do anything they want to your apnaerapce. Give them the best show you've got. Of course SNSD and the like were nowhere near where they are now when they auditioned. Ask yourself how much you really want it and how long you'll want it for, though, there are trainees behind the scenes that work hard but never get to debut, the idol life only lasts around 5 or so years, and the work hours of an entertainer are comparable to those of factory laborers at the turn of the past century. I wish you all the best if this is what you decide is what you really want!