Being 15 and in the 8th grade isn't that big of a stretch. I was 14 when I was in the 8th grade. Growing up in my school district, if your birthday fell after a certain date (I think it was September, but I can't remember that far back
), you had to wait a year to start school.
In any case, my prayers are with the young suicidal man, the injured "hostage" and everyone affected by this incident. Its so sad that someone so young felt that this was his only option. But then again, I know that when you are suicidal, you are not in your right state of mind.