Hi, new to the idea

My name is Sara. I'm almost 30 and have been married for almost 12 years. My DH is active duty U.S. Army and just got back from a 15 month deployment. We are now preparing for a PCS to Colorado (We currently live in Texas). We have two little munchkins already, our oldest (DD) is almost 11 and severely autistic with a diagnosis of MR and our youngest (DS) is 6 1/2 and mildly autistic. We have been trying for 5 years to have our last child and I was diagnosed with PCOS while he was gone. We finally have felt that it is time to give up the dream of having our final child biologically. The whole idea of adoption is pretty new to us, it never felt right until now, so I never gave it any thought. We will be going through this process in Colorado and I'm seriously lost at all the information, what to do. We know we want to do a domestic adoption, but other then that, we have no clue. I hope I can get some good advice and pointed towards some good conversations on this forum. We are leaning towards a Christian based agency, but still nothing is decided. It's nice to meet you all! Sara