Some people are really naive when they enter the industry. I know I was, though I was 18, I didn't even know what aw was. I just rang round a few agencies and went with the one which seemed the nicest, and testament to them I still work for them, because they are brilliant and I'm fortunate for that.
Plus I know when I was new I felt like they were keeping me safe (I learned quickly that it isn't the case though)