If you look at spacetime as possibly forming a Compact Lorentzian Manifold, then time could have a curvature. Extrapolating linearly backward in time by 13.7 billion years could be meaningless. So no, I wouldn’t bet my life on it.Would you bet your life on it?
Big Bang proof supposedly came from:
2. Cosmic Background Radiation
3. Deuterium and baryogenesis