Apparently she was never inside the home, which presents a different picture:http://www.sun-sentinel.com/local/miami-dade/sfl-teen-burglary-fatally-shot-20160311-story.html
https://www.washingtonpost.com/news...ar-as-he-fled-her-home-should-she-be-charged/
Ok, that does present a different picture indeed.
Directions now are very important. He was fleeing her house--but she was also outside. If he ran at her ("a confrontation" as originally reported) she's got a reasonable fear of harm and is justified. If he ran away from her it's murder.
And finally, I somewhat agree with you.
He was shot in the chest, which does indicate that he was coming in her direction - but that does not necessarily mean he confronted her or was coming 'at' her, though.
According to most reports, she was circling the outside of her house. Did he rush out the back door just as she happened around to the back of the house? I can see her shooting him more or less accidentally even though he was not actually a threat to her. That would not be "murder" but not "self-defense" either.
Did he indeed "confront" her or act aggressively? That could be self-defense on her part even if they were outside.
Did she try to stop him from leaving (a/k/a “Fucking punks. Those assholes, they always get away.”) and "arrested" him by killing him? That's murder, imo.