Zimmerman was following Trayvon.
Yes...
Trayvon knew he was being followed.
Yes...
After having been followed, he's now confronted. How is that not grounds for fearing what's about to happen? If it was a girl, should she wait to see what this man following her has to say after having followed her. Let him get right up on her and see what he's all about in the middle of the night. She's most likely going to end up raped and in a ditch. Why is it different for Trayvon? He knew he was being followed from the start. Then this dude actually gets out of his vehicle to confront him. I'd assume I'm about to get stabbed or mugged in that situation. I'm not waiting to see what someone has to say after they've been following me. Self-defense... he felt threatened. And rightfully so.