It seems that Luke (2:49-50) knew this difficulty, since he specifies that the baby Jesus knew perfectly the "things of the his own Father" the first time in the Temple.
The self-awareness of Jesus even in the apparent human birth is found in the Ascension of Isaiah. But was it part of the original belief?
I think that the original Ascension of Isaiah may be an old document even if it had the story of the birth of Jesus. Really just in virtue of that.
So it reads:
7And after two months of days, while Joseph was in his house, and Mary his wife, but both alone, it came about, when they were alone, that Mary then looked with her eyes and saw a small infant, and she was astounded. 9And after her astonishment had worn off, her womb was found as (it was) at first, before she had conceived
This Mary is very similar to Eve when the her eyes were opened by the Serpent.
This may be a sign of the gnostic nature of the original document of the Ascension of Isaiah
It seems that the gnostic clues are also found in the following passage:
10And when her husband, Joseph, said to her, "What has made you astounded?" his eyes were opened, and he saw the infant and praised the Lord, because the Lord had come in his lot.
Mary and Joseph believe that the son was from the creator god (they "praised the Lord", afterall), but, in virtue of the fact that also their ignorance has to be assumed about the Son, then the Son has to be from an alien god, different from the creator.
Hence the original gnostic nature of the document.
Question: was the Mark's separationism a way to make Jesus unaware of himself, by de facto separating him from the his divine nature and so making him really who the his relatives believed that he was: a mere Jew from Galilee?