More than that. Mary would, being a woman well-educated in her faith, have consciously had in mind the numerous previous examples of angelic announcements of impending births - Isaac, Samuel and Samson. This is evident from her prayer of praise to Elizabeth - ‘my soul glorifies the Lord …’ which very much borrows from the prayer of praise Samuel’s mother offered to God, as recorded in scripture.
In none if these precedent births was the child conceived supernaturally, despite the angelic announcement, in all cases the child was conceived as a result of marital relations. These were the cases Mary would have been thinking about. Hence her confusion since she not only was a virgin at the time but intended to remain one afterwards.
