There is a genetic Adam and Eve. However, I don’t think they existed at the same time. These were humans, not just apes/mammals/animals/bacteria. We are all distantly related.
We are also more related to mushrooms than trees are to mushrooms.
Yeah, it’s hard to pin down when these common ancestors lived precisely, especially given that as portions of our genome go extinct, the common ancestor will change.
But Y-chromosomal Adam is estimated to have lived around 200,000 years ago, while estimates for when Mitochondrial Eve lived are a bit more recent, around 150,000 years ago.
According to an unverified internet search, the average age of childbirth for women throughout history is 23.2 years, and for men it is 30.7.
So, statistically, your great^6463 grandmother is the same as mine. Same goes for our great^6512 grandfather.