Listen to this statement of what you termed “poetic liberty” in the Evangelium:
“But Mary had forgotten the mysteries of which the archangel Gabriel had spoken, and gazed up into heaven, and said: Who am I, O Lord, that all the generations of the earth should bless me? And she remained three months with Elizabeth; and day by day she grew bigger. And Mary being afraid, went away to her own house, and hid herself from the sons of Israel. And she was sixteen years old when these mysteries happened.”
An angel from God visits and announces one of most momentous events in human history to Mary and....oops! she forgot! AND SHE FORGOT! FORGOT AN ANGEL'S VISIT AND HIS MESSAGE!
Shall I go dismantling this fraud? It's like a one legged table, stand back from it and it will fall over on its own.
I prefer you not jump threads but post your specific questions about the Protoevangelium on the thread dedicated to it. Also calling it "fraud" does not make it so.
The conjecture that Mary "had forgotten" the "mysteries" of the Annunciation is indeed a psychological elaboration that rings false. It is an artistic attempt to give a background to Mary's Magnificat (Luke 1:46-55), which it proceeds to quote in part. It does not discredit the factual content of the book.
Let us also remember that Mary is not free from human weakness; she did, for example, forget her child in the Temple. According to the Protoevangelium, she did not forget about the Annunciation altogether, but "of the mysteries". Her subsequent speech explains that her perplexion is not of her mission, but of the fact that it is she who was chosen for it. It is a reasonable and humble attitude, same as when she is rebuked by St. Joseph and answers obliquely.