Should Mary have told Jesus that Joseph was not His father, and when did Jesus know?

Those who understand the hypostatic union to the maximal degree would say Jesus already knew He was not the physical son of Joseph, only His legal son. But then you get into the question of a young child. If Mary is wondering whether to say something when He is four, or three, or two, you would base your thinking on the fact that He is a young person; a normal child that age would not understand what it meant, because they do not yet understand procreation. If you told a two-year-old and He understood, that could only be because He understood as the Son of God, and the question then is whether that divine knowledge is transferred over to the son of man even at that age; you get into really hairy territory trying to figure out how the hypostatic union works in such cases. Consider Matthew 24:36 and Mark 13:32, where Jesus says that no one knows the day or the hour, not even the angels, nor the Son, but only the Father, and Acts 1:7, where He tells the apostles it is not for them to know the times the Father has set. Some theologians who take the hypostatic union to the nth degree say Jesus really knew, because He is God, but I do not take that position; I take Scripture for what it says. So there are things the Son does not know in His human nature. It may be that Jesus' human intellect came to understand who His Father was as it developed, perhaps by age twelve, having read the prophecies about Himself, rather than necessarily being told or prompted by His divine nature.