She told Sligo Circuit Court the abuse she received in third class had "left its mark on me".
Sr Mary Theresa Grogan, formerly known as Sr Peter, has denied 63 charges of indecently assaulting seven young girls in the 1970s.
In evidence today, one alleged victim told of her horror when she was trapped inside the school library with the accused nun.
She said the nun grabbed her and assaulted her. She said: "I don't know how I got out."
During a reference to separate civil proceedings the woman said: "This is not about money. No money can pay for what Sr Peter did to me."