You don't 'truly believe in the big bang' lmao. You just understand that is the best theory we have today out of all the evidence we have. There are other theories with merit. We need more data and evidence, and either the big bang theory becomes stronger or weaker. Anyone 'believing' something impossible to prove is an idiot, whether that belief is that a god wiggled his nose or a scientific theory. Accept that we don't know everything.