School shootings are actually pretty rare, though you would never know if you listened to gun control groups.
USA Today recently illustrated the point, even while attempting to sensationalize the topic. In a story titled “Deadly school shootings since Columbine”, the paper created a timeline showing when such events occurred. I suspect their goal was to make each tragedy easy to find and read about.
What it really showed was how infrequent such events are. In the slider bar at page top, there are multi-year gaps between such events. This matches data from the federal government that noted a low mortality rate and a steadily falling rate of school deaths.
This is one point that needs to be stressed: Things have been getting better for the past couple of decades. Violence against children is falling, with the occasional lunatic mass murderer causing angst. Statistically speaking, your child is safer than any time in recent memory.