Naming ceremony is an old tradition. A name is given in an old language. It is only held for those who are worthy. Naming ceremony is held when boy turns fourteen.
For a naming ceremony, boy needs to have a Man sponsoring him and twelve other Men who think him worthy as well. It isn't allowed to write about the rites, but it has to do with choosing the fate of animals, brought to be sacrificed. Fitz chose to let all the animals live, which meant that there was nothing to eat in his ceremony. He did get a name, which translates as Changer or Catalyst.