Someone please check the age of the child that was left at home and post a link. I believe it was reported he was 7.. JMO
He is now 15, so 13 or 14 at the time, depending on when his birthday was:
The first witness to take the stand was 15-year-old Chad Joseph, the son of Martin's father's girlfriend. Joseph testified that he and Martin were playing video games before Martin left the home to go to the store.
http://www.wftv.com/news/news/local/day-10-first-witnesses-called-george-zimmerman-tri/nYTC8/