It was terror that shook the nation. On Sunday, Sept. 15, 1963, a bomb exploded in the basement of the Sixteenth Street Baptist Church in Birmingham, Ala. Four little girls, all dressed in white — 14-year-olds Addie Mae Collins, Carole Robertson and Cynthia Wesley, and 11-year-old Denise McNair — died in the explosion, and are remembered in history. Congress now is considering offering them posthumously a Congressional Gold Medal. But there was a fifth little girl caught in the blast — 10-year-old Sarah Collins Rudolph — the younger sister of Addie Mae. Partly blinded, she staggered from the basement bleeding …