In order for you to have a published Regular, Quick or Blitz rating, you must have played at least 4 rated games at a time control that is Regular, Quick or Blitz rated, respectively. (Also, some time controls are both Regular and Quick rated, these are called dual-rated time controls.)
You are still considered ‘Unrated’ until your rating has been published in a monthly ratings list. We issue ratings lists every month. At this time, the next month’s rating list is generated on the third Wednesday of the month before it becomes official.
To give you some idea of the time lags involved, the December 2013 annual list, which is the list TD’s are generally required to use for events held in December, will be created in mid-November and will include events received and processed through mid-November.
So, if your first event is in late November of 2013, you would still be unrated until the January 2014 Rating Supplement comes out. That means that you would still be considered unrated for events held prior to January 1st.
For your first 25 games, your rating is provisional. A provisional rating is indicated by a slash and the number of games upon which it is based. For example, a rating of 1213/16 is based on 16 games. (However, read the earlier answer on how Quick or Blitz ratings are started.)