it's good to believe in God. it's bad to use Him to explain things you don't understand in science.
things don't evolve by accident, they evolve because it's their nature to do so. "accident" is a part of the process, sure, but that doesn't make it less natural.
the big bang is one theory, you can take it or leave it. evolution doesn't depend on it. I think it's fundamentally flawed in that it thinks the second law is so universal everything must be downhill from a single point. rather I think the second law doesn't apply within certain super-dense energy concentrations such as black holes, so the universe is really eternal and symmetrical. saying the cause is "outside time" is absurd because time is necessary to cause something.
similarly for the cause to be complex and well designed enough to make life begs the question. what made it that complex and well designed? calling it God is just a convenient way to quit thinking about it, it's not a real explanation. God is the reason for everything, not just what you don't understand.