Welcome CB. I've also struggled with the concept of a Higher Power, in the sense of some supernatural force outside of myself takes an active interest in my life and doings...and were it not for the notion that I could choose whatever concept of "God" I wished, I would never have made it past the Third Step and I would have closed the Big Book halfway through the first chapter. Have you read "We Agnostics" in the Big Book? It helped me come to terms with some issues I had. It's hard to deny that their are powers greater than myself all around me (gravity or the sun, for instance). I've heard that most people who have a problem with the concept of "God" choose to use their AA group as their Higher Power. Don't let this hold you back. I've rarely read an introductory post on this board from someone who seems as optimistic and prepared for recovery as you.
--Fenris.