That’s a good example, but check out Big Joe Turner’s “Roll 'Em Pete” from 1938.
See, that to me is just straight-up boogie woogie piano. Definitely on the road to rock and roll, but not quite there yet.
It’s impossible to say what truly is the first rock song. As quickly as rock and roll caught on, it was still an evolutionary process. I don’t think you could find a discrete moment when all of a sudden it was “rock and roll” and no longer just a mix of influential genres.
Totally agree – it’s fun to find examples of stuff with the rock ‘n’ roll sound from before the “era”, but no way is there one “first rock ‘n’ roll record”.