On my 18th birthday, I walked into a ballroom full of balloons, music, and cameras—only to hear my sister laugh, “Surprise! I’m turning eighteen again tonight.” My mother smiled and said, “Just let her have this, honey.”

moved through the crowd, and a large banner read “Happy 18th Birthday!” For one foolish, hopeful moment, I believed they had finally picked me. My older sister, Vanessa, had always been the pretty one, the emotional one, the one who made every room revolve around her. But that night was supposed to belong to me.

Then I entered and saw her standing in continue reading …