I forgot to mention, this is how she and why she was conceived without sin...as Eve was. For no other mortals besides [pre mortality] Adam and Eve was this bestowed upon. Jesus is God so we cannot exactly put Him as a mortal.
AS bearer of God, He kept Her pure for this purpose to bear His only Son.
So it was not a sin to accidentally leave the son of God behind and go on to another city? In today's society, wouldn't a mother and father be charged with something in the court system for leaving their child behind? Perhaps she was busy watching all the other children she had with Joseph in their marriage relationship.
Luk 2:43 And when they had fulfilled the days, as they returned, the child Jesus tarried behind in Jerusalem; and Joseph and his mother knew not of it.
Luk 2:44 But they, supposing him to have been in the company, went a day's journey; and they sought him among their kinsfolk and acquaintance.
Luk 2:45 And when they found him not, they turned back again to Jerusalem, seeking him.
Luk 2:46 And it came to pass, that after three days they found him in the temple, sitting in the midst of the doctors, both hearing them, and asking them questions.
Luk 2:47 And all that heard him were astonished at his understanding and answers.
Luk 2:48 And when they saw him, they were amazed: and his mother said unto him, Son, why hast thou thus dealt with us? behold, thy father and I have sought thee sorrowing.
Luk 2:49 And he said unto them, How is it that ye sought me? wist ye not that I must be about my Father's business?
I'd say that's at least a small spot on the ol' perfect record. She, like us all, was only made perfect by faith, not works. Her works were not perfect, and she like us all sinned, this being one instance, leaving Jesus behind. Another instance was at the wedding at Cana when she presumed that Jesus didn't know they needed more wine, doubting his omniscience.
Joh 2:3 And when they wanted wine, the mother of Jesus saith unto him, They have no wine.
Joh 2:4 Jesus saith unto her, Woman, what have I to do with thee? mine hour is not yet come.