Some of us believes the theory of the big bang some of us don't but either way we should respect each others ideas and thoughts. But in my opinion these might be some evidences that can prove the big bang theory.
1. The Night Sky Is Dark
If our universe existed forever, the night sky would glow as bright as the Sun. So it must have a finite age.
2. It Is Expanding
Since the space between galaxies is expanding, it is logical to think that once they were closer. In fact so close that everything existed as a single point of infinite density and temperature.
3. Quasars Exist
The distant universe appears to be very different and chaotic than the nearby universe. Quasars (super-massive black holes feeding on large amounts of matter) are common in the distant universe.
4. Cosmic Microwave Background Radiation
The entire universe is uniformly filled with microwave radiation. It is high energy radiation emitted by the baby universe that cooled over the years.