Even if that's what it all hung on, the 40 year thing just dosen't work. For how long was it from the time Eve was created, till the time she eat the fruit, 10 years, a few decades, 100 years? Nothing in the bible, tells either time frame, nor dose it give a time frame for when Adam was created, just because the Jewish calender points towards a date, for his creation, dose not make it so!
Before D day in 1944 only 2 people know for sure when it was going to be, lots of guessing, but until the order was given, the allied army's only knew it was coming!
Dwain