This films invites viewers to consider the lives of Mary and Joseph as the parents of Jesus. Yes they knew he was set apart as God's Son, but they likely did not have a full understanding of what that entailed in the responsibility. Also regarding Jesus' growing into His divinity-this would is not adding to Scripture as it would be supported by his being fully human. The incarnation was to provide salvation for creation but also to offer God the experience of humanity. If Jesus had perfect knowledge immediately then his human experience would not be genuine, as humans do not have full knowledge, or especially understanding.