Without an eyewitness to the start of the fight, everyone is just speculating, including the both of you, and me.
based on what you want to believe.
Once again, that includes EVERYONE, because we all use whatever info we can gather and come to a conclusion, often biased based on experience, because... that's how the mind works.
Consider this, if you both will.
Martin had Zimmerman on the ground (there is both evidence and testimony to that part) and (speculation) Martin grabbed for Zimmerman's gun, Zimmerman tried to keep him from taking it, and Martin is actually the one who pulled the trigger. Amateurs , such as young/innocent Martin, would grab from someone else by reaching for the trigger, using their thumb. Unfortunately, that leaves the gun still pointed at YOU.
But what counts is what can be shown through testimony and evidence and how it weighs against reasonable doubt. Example- let's say Zimmerman testifies that TM hit him in the nose then got on top of him and smashed his head into the ground (the police report shows a bloody nose and cuts to the head, and a witness says they saw Martin on top of zimmerman.) Now lets say TM's defense attorney in closing says-- "I think Zimmerman swung at martin and missed, that's why martin hit him in the nose, it was self defense" Well maybe, but without testimony or evidence to support it this is speculation and would not surpass Zimmerman's presumption of innocence and the courts standard of reasonable doubt.