Trayvon wasn't shot walking down the street - according to police and eyewitnesses, he was shot while getting the best of a man half a foot smaller than him. According to the law in Florida, in a self-defense case, TM would be considered an adult, not a child.
I've looked, and I can't find a single case where a child was actually walking down the street and was shot by the owner of a concealed weapon - less than none where SYG law was a defense for such an act. However, cases where children and dozens of teenagers have been shot just walking down the street, riding in a car, or sitting outside/inside their house are countless. Where Trayvon lived, 7 innocent people were shot attending a funeral - there were 30 murders in March alone. In every case the shooters were armed with illegal firearms. Where's the outrage by either side??
Very few concealed handgun owners shoot innocent people. JMO
Disclaimer: The above is not an effort to make excuses for GZ and I truly am not trying to argue - I just can't "guess" what happened, I have to go by what has been said by LE & witnesses. As far as who confronted who - LE has stated the g/f's phone records are not consistent with what they have.
JMO