I take it you're not black then?
I definitely agree that the girlfriend's testimony doesn't prove Zimmerman threw the first punch. He might've touched him first though and that's what would likely bury him even with jurors who are more inclined to believe his story.
Really, I guess I'm just trying to work out in my mind why else Zimmerman would go on to lie and exaggerate if he hadn't done anything wrong. If he had gone up to Trayvon and said: "Excuse me, I couldn't help but notice you walking around here and you seemed a little bit lost. There's been a rash of break-ins taking place in this area and I was just checking to see if you're okay." and then Trayvon just started kicking his teeth in he wouldn't be lying about so much of what happened. You know?
The girlfriend did say that Zimmerman answered Trayvon's question with the words "What are you doing here?" before the headset fell. That's kind of why I'm thinking that Zimmerman maybe grabbed the kid's arm or something before Trayvon punched him.
I've noticed that a lot of the Hispanic people I've met tend to be more physical in general with respect to touch and all that so from that perspective Zimmerman might not have been fully aware of the effect his actions were having. The kid reacts badly and things continue to escalate from there.
Of course I also don't really care about the details of the fight because I think Trayvon had every reason to feel threatened and since he only had his fists and he wasn't some kind of expert martial artist I just don't think Zimmerman's use of deadly force was justified here.
That said, I think the right charge was probably manslaughter. Unless there's some unreleased evidence (apparently it's been sealed) that we don't know about Murder 2 seems like reaching to me.