Oh my gosh! I so identified with this! I climbed Longs Peak for my 50th birthday in 2005. I too felt the extreme fear as I stepped through the keyhole onto the ledges. I went away down. Maybe 300 yards and set down on a rock, saying I couldn't go on. A woman came along who I did not know, and did not see on the trail again. She held my hands and hers, looked me in the eye, and said to my soul, "you can do this!" Speaking to my heart as she had, I ventured on. The fear was still there but I was able to overcome and made it to the summit!