Okay...a few things.I have narrow hips, no waist, typical athletic body. I'm short, small framed, all that. I birthed my son vaginally and he was about 9 lbs. Also, I pushed him out in 15 minutes and he was my first (I pushed on my back too, silly me). My second, who was just under 8 lbs., I pushed out in 20 mins on hands and knees and she was a waterbirth. I think prenatal yoga was KEY for me. It just really worked on opening up my pelvis and making it easy for me to get into positions that were optimal for birthing.
It's so hard to be in the position you're in as a "patient" in labor. To have to advocate for yourself while trying to concentrate on the most intense physical and emotional event of life. When the "experts" start telling you you're baby is in distress, decels, you may feel really helpless and you are definately in an extremely vulnerable and persuasive state. Many times we're afraid not to listen. When you're in the hospital the burden is on you to know when things are truly emergency, or if it's just hospital staff being overly cautious, impatient, etc.
Do yourself a favor, stay home. Trust your body. Begin a journey to heal yourself from your hang-ups about your first birth. Really work to get away from the fear of labor, and move toward liberations and empowerment. It is a spiritual/cosmic journey. You CAN do this!