It's not something you can just Google, as there's no real evidence for it, only circumstancial pieces of a puzzle.
The first is that, as KR implied, Adam and eve did not have sex until after the Fall. Second is that Adam only lived to be 929 years old, which would throw out the "thousands of years" theory.
Third, Eve was created perfect, meaning her menstrual cycle would have started the day she was created, aka Day 6, with no issues at all throughout. Extrapolate that out, and the earliest she could have had conceived would be very early on indeed, less than a month.
Fourth, throughout the Bible, the number 13 has signified rebellion and lawlessness.
Fifth, still pertaining to the number 13, is that it has remained ingrained in humanity's memory that 13 signifies something bad.
There's more to it than that, but it's all I can remember off the top of my head at the moment from the Bible Study.