Was there ever a very first Homo sapiens?
No. It is important to distinguish "species" as a human system of classification, and "speciation" as a biological process. Except in cases like chromosomal speciation (changes in ploidy), speciation takes a long time. Probably thousands of years between some initial restriction of gene-flow, and fixation of a specific identifiable trait, present in all individuals of a species, and not present in any others. As a human system of classification, the taxonomists who define species would all understand that speciation is a process that occurs over time, although they may make some arbitrary distinction for convenience. For example, a node on a cladogram symbolizes an instantaneous process of species bifurcation, but this is understood to be an unrealistic simplification.