ACIM Resistance

I am finding I have some resistance to ACIM (A Course in Miracles) for a number of reasons. First of all, I've never been a close follower of Christianity, it never rang true for me. So all the talk of guilt and sin and Atonement and other Chrisitian terms I find difficult to understand and relate to let alone accept. My second big resistance is reconciling years worth of study of other spiritual/mystical teachings and experiences with the fact that ACIM says they are not real. I have a hard time accepting that my journeys in what I perceive as the spirit world and conversation and knowledge I've gained from spirits are as much a part of the dream as the "real world." But I am commited to giving this a chance and seeing how it may change my life. It is more important for me to be happy than for me to be right. I have always had the goal of becoming one of those peaceful people who do not react to life with anger and frustration and the Course does seem to guide you to that state in a very gentle and step by step process. Even the workbook repeatedly says, you may not understand or accept this yet but right now it is the practice that is important. And so I will continue to practice.