I considered myself an atheist, then an agnostic. I label myself a Pagan now, studying the Craft and at the same time to become a Wiccan priest. People grow and change. There are elements of my belief set that include some parts of Christianity. Part of that is due to the fact that at one time Paganism and Christianity shared different aspects of each other and it only seems natural. There are way that they still share. One does not have to preclude the other, and I know a few people who label themselves "Christo Pagan," or any number of other combinations of religions.
As for choosing a God/dess or simply just Deity, who, what, or how to worship, or not, is a choice each individual makes. I have learned that one takes what they can use, what might make them happy, fulfilled, or at peace and leaves the rest behind. There are so many paths to follow and many have no name at all.
As has been mentioned, the belief that there is one true way is not shared between many groups of people. The way is what works for you.