We study the quantum cosmology of a five-dimensional non-compactified Kaluza-Klein theory where the four-dimensional (4D) metric depends on the fifth coordinate, x⁴≡l. This model is effectively equivalent to a 4D non-minimally coupled dilaton field in addition to matter generated on hypersurfaces l = constant by the extra coordinate dependence in the four-dimensional metric. We show that the Vilenkin wavefunction of the universe is more convenient for this model as it predicts a newborn 4D universe on the l≃0 constant hypersurface.