Don't go down that road. It is possible to believe both.
It sure is. Not only is it possible to believe both, but "Big Bang" was a name given to the theory that the Universe started at a single point to ridicule it because for some cosmologists who believed the then dominant theory of stasis, a universe that came from a single point and exploded into existence sounded too much like "God said, let there be light". That the person who proposed the theory, George LeMaitre, was a Catholic priest, sealed the deal for the need to ridicule. Turns out Father LeMaitre appeared to have it closer to right than the stasis theory. An interesting tidbit.
edit: Corrected for grammar