I am still an agnostic, only because god or big bang aren't the only two beliefs that I think our possible. I have, I think, found a contradiction to god. This might not be a ground breaking discovery but I don't see anyway to refute it so it's proof enough.
Now considering if God existed he could do anything, just like all religions agree he does, and hypothetically if he were to remove that power to do anything (become mortal) well then doesn't that mean he is impossible to begin with? Because now he could not get those powers back and thus could not actually do everything or anything.