so the ominiscient God had a little black book of backup dates just in case Mary didn’t pan out? If so, how’d he rank them? Is this some new part of the Bible you found on wikileaks?
the parable of the virgins, is Christ talking about some Marys?
Each generation of the Jews waited, still waits, for Him to come. He would not come to a spiritually impure nation. Finally He revealed to the prophet Jeremiah the date, and let Daniel interpret the prophecy. The Jews who were baptized by John fulfilled the "virgin" clause.
This is bible scripture, but I'm sure you can find it on the wikiwacki site if you dont have a bible.