Evolution has been proved time and again, we can see it happening and continuing on today.
What is in dispute is the Last Universal Common Ancestor, which would be some organism from which life today was generated from. The last point you can trace all life back too. We can theorize what the lifeform would need to be like to enable us to exist, but finding it will be hard.
So how did the world form? We are the left over result of the accretion of a stellar death many billions of years ago, have a read about how Solar Systems form, very cool gear. The Big Bang works fine, but since time was created at the point of the big bang, there is technically no before. Which is where human brains go splat.
What I think we have to consider is that parts of our existence may be, at least for now, beyond our understanding. You could teach calculus to a pigeon until you are blue in the face, but it will never understand. Only human arrogance makes us think we can understand everything. We are still pretty low on the evolutionary scale.
In answer to your question, I follow science. As more information is discovered, we change the theory to match, that's how we learn. There is a misconception in the word "theory". Evolution is a theory.
So is gravity. In the words of Tim Minchin "Those who doubt evolution cause it's only a theory, you hope they feel the same about gravity. So they might float the #### away."
The more science you read, the more it makes sense. The more religion you read, the more you think it's a crock.
