Mine is the same age. She hold it quite good and knows where to go; yet sometimes she will make mistakes especially if I am not close to the door. She sometimes ring the bell, sometimes just give me that "look and run" as her potty signal. If you missed that signal; accident happen. I guess it is what I call learning. The bell helps and obidience class also helps. See my previous post about the bell
http://www.yorkietalk.com/forums/sho...highlight=bell