This article critically examines the interpretations of cosmic microwave background radiation measurements and the resulting findings regarding the "flatness" of the universe. The author raises a fundamental question: should the concept of curvature apply strictly to spatial dimensions, or must we also consider the curvature of the temporal dimension within the integrated framework of spacetime? The core argument challenges the prevailing cosmological assumption that the passage of time has remained uniform since the Big Bang. While standard theories describe events in fractions of a second shortly after the universe's origin, they implicitly assume these units are identical to modern seconds. However, given that early cosmic conditions mirrored the extreme gravitational environments of black holes—where time significantly slows down or stops—the author suggests that time in the early universe may have been initially very "slow" and only accelerated over the course of subsequent evolution. The piece invites a reassessment of whether a "flat" temporal metric is a valid assumption for early cosmology or if time itself underwent significant evolutionary acceleration, questioning the silent presumption of a constant temporal flow throughout cosmic history.