please refer to the thread titled 'Important Dates 2013' and you will find your answer.
You don't need to start a new thread for every thought that comes into your head. The USyd website can also answer pretty much all the questions you post in this forum.
so just 1 more question, if i change my courses and get a new timetable will it be bad because all the classes are full right now and it wont give me much optiosn??