Correct me if I am wrong but don't you have to take a level of half off paragon before you take off paragon seeing how your a half off?

From the srd; Divided Ancestry (Ex)

Unlike other racial paragons, half-orcs can take levels in more than one racial paragon class. After gaining at least one level as a half-orc paragon, a character can take either orc paragon levels or human paragon levels (but not both).