In "The Leap", what are the "three times" the narrator describes by which she owes her mother her existence?

The narrator says she owes her mother her existence the first time because of an incident that occurred before her birth.  Her mother, Anna, of the Flying Avalons, was a trapeze artist.  When she was seven months pregnant, she was performing the finale of their act with her husband when the circus tent was struck by lightning. Falling, Anna grabbed a guy wire, which was superheated by lightning.  She was confined to a hospital for a month and a half, and her daughter was stillborn.  Throughout her lifetime, the narrator considered this daughter, her half-sister, as a part of her own existence, "a less-finished version of herself".

While she was in the hospital, Anna met her second husband, a doctor, who was the narrator's father.  The doctor taught Anna to read while she was hospitalized, and they fell in love.  The narrator refers to the fact that her mother gave birth to her as the second reason she owes her for her existence, this time in a literal sense.

The narrator owes her existence to her mother a third time because of an incident that occurred when she was seven years old.  The narrator was home with a babysitter when their farmhouse caught fire.  By the time her parents returned home, the house was engulfed in flames, and there seemed to be little hope that firemen would reach the narrator in her room because their extension ladder was broken.  Undaunted, Anna used the broken ladder to climb an elm tree near the house that had a branch that brushed the roof.  She crawled along a bough above the branch and leapt towards the roof, landing on it and, using her acrobatic skills, hanging from the rain gutter over her daughter's window.  Anna entered the narrator's room, and, clutching their daughter, jumped from the window into a safety net below, saving her life.