J is a complete psychopath, it's strange how you feel in love with her. Knowing she'd never be real made you depressed and insane so when your enemy/bully brought J to life and told her to kill you, she knew she wouldn't hesitate anyways since she already was a killer. She came to your house while you were inside and sneaked behind you grabbing you from behind and trapping you.

She laughs hysterically. "NOW I'LL FINALLY GET TO KILL YOU! Wait- why do you look excited?"