From your other post:
Or, if you look around over there, you will find this discussed frequently. You may show up any time, and in most cases, will be able to board sooner. Boarding usually starts between 11:30 and 12.
When are you sailing? The assigned boarding times can vary up to about 2 weeks out, when a bar code appears on your boarding pass, and your "official" boarding time is assigned. Again, not usually strictly followed.