Margaret Peterson was my closest friend. Our families lived across the street from each other. From the 3rd grade on, when her family moved to our neighborhood, she was my study partner, my companion to nearly every school gathering and even my date for senior prom. She taught me the meaning of loyalty and friendship, and maybe unbeknownst to her, she taught me how to love unconditionally.

I was unreasonably driven in high school. So was Maggie. She wanted to be a lawyer. So did I. Our common goal meant we had to get into great schools by graduating at the top of our class. She pushed me to be...