I would definitely try to be there at opening,Sea World is different from the other parks in that it has a lot of shows so you should get there at opening grab a park map and plan your day around the showtimes leaving time to do the rides and coasters and to eat.November 13th should be OK crowdwise as the Thanksgiving crowds are not there yet so the rides and coasters shouldn't have long waits.Getting there near opening should allow you to see most of the park,planning the day around the showtimes is the most important thing.