5 options
1.) Adam & Eve
-self explanatory
2.) earliest possible form of life
-self explanatory
3.) earliest form of matter/existence
-based on the concept of life being only an emergent function, and therefore you being descended from literally rocks and space dust
4.) earliest human
-the earliest recognizable member of the human genus or species
5.) earliest member of your family to cleave himself off from another group
-this would likely seem arbitrary if you don't know anything of your roots, but it could be very clearly where your lineage went from being a part of a group to being a group