I don't know where this comes from

The gunshot changed everything.

I ran.  Out the door, to the left down the corridor. My feet pounded on the tiles.  My heart -- I can't remember anything beside the terrified thudding in my ears.

Out. Out! 

Bursting through the glass doors, I fell to my knees, gasping, sobbing, blinded at last by my own tears.  Someone gathered me up as if I weighed nothing before dashing down steps, over wet grass that made him slip -- then recover -- and deposit me with an EMT.

I didn't need medical attention....  Not me.

--
It's been a year since then. A year. Sometimes, I want to kill myself. I feel bereft of value.  Useless. As if people are expecting me to be someone I'm not.  As if they're measuring me, asking themselves if I was worth it.

"Me," she told the gunman. "Me.  Let her go."

I ran.

I am not her. NOT her.  I can't BE her.  But killing myself will only invalidate her sacrifice.

I can't do that.

She was my best friend.

Today is my eighteenth birthday.  They tell me I'm a grown-up, now. An  adult.  Truthfully, I grew up last year, when I learned that my life wasn't just mine. 

It's hers, too.