In the unlikeliest of places. This would change everythingThere are three possibilities if it's real.
Life could have came from Earth 4 billion years ago. We had huge impacts and tons of extremophiles that could have potentially survived the journey. If that happened, then this is still an incredible discover but wouldn't change much.
Also possible the opposite happened. Maybe life started on Venus and an impact brought life to Earth. That would be crazy knowing that we were "born" on Venus.
Third possibility is that life on Venus is independent. That'd change more than everything. Greatly increases the odds of there being intelligent life out there that is far more advanced than us.