I don't agree with that. Your not within your rights to turn around and attack someone who is following you. You can turn around and ask what they are doing, or within your rights to continue to flee from the person or contact 911, but you can't just turn around and jump on the person and start hitting them... that makes you the aggressor.
No one except GZ has said Trayvon did this. No one knows for a fact how the confrontation transpired. That's why the jury is hearing this case.
The second question is whether, if the above assumption is true, the use of deadly force (shooting in the heart) was warranted. And I don't mean warranted in our opinions. I mean legally warranted.