How?

I have always wonder about how God exists. Sure, for those who believe, God has created the heavens, the earth, the universe and every other thing that exists in the space. But did He created Himself? By saying this I do not mean that I'm doubting His existence or power, because I do believe that He creates all things and is all powerful. But has He always exists from the very beginning (okay, more like for all eternity), or has He one day decided to come alive and therefore willed Himself into life? Of course, no one has created Him because He is the one who has created everything, which means that if He does not create anything, nothing can create Him right? So it must be He Himself. I just think a lot about whether it is His decision to exist and if it is, why has he chosen to? It is just so hard for me to fathom the fact that He has always been there, for infinity. Way, way, way before any other thing exists. Way before there is time. I mean, how do you count infinity?