Here's a timeline of post Columbine shootings
Since 2015, school shooting incidents in the U.S. have skyrocketed compared to previous decades. So far in 2024, there have been 144 shooting incidents at
www.security.org
They pull data from here
K-12 School Shooting Database documents when a gun is fired, brandished (with intent to harm), or bullet hits school property
k12ssdb.org
Which also seems to have some good data on school shooting from '70 going forward. The issue of going backwards prior to around the '70s is quality of record keeping and digitization of data. It's always good to have a larger data set to better understand trends, but that's pretty hard for gun shit. As well as what you and others have mentioned on what actually constitutes a "school shooting."
Right at the top of the page k12ssdb says they "
includ[e] gang shootings, domestic violence, shootings at sports games and afterhours school events, suicides, fights that escalate into shootings, and accidents." This is across all time for their definition of school shootings.
It seems most school shooting situations are "escalation of disputes" in parking lots of sporting schools/their sports area and the shooter has a 25% chance to just not have any relation to the school...

so gang nigs do gang nig shit, the data we do have shows a slow increase in violence ( didnt check if per capita increase ) until around columbine then it goes up pretty good and again into the 2010s goes up more biggly. We know a lot of them are some form of copy cat/inspired by the media's sensational reporting. At the same time this could be due to increased reporting/access to information broadly. But the conventional "school shooting" does seem to be on the rise but it's still not that big of a deal when brought into broader context.
There are around 40k dead via guns a year. 1/2 to 2/3s is via suicide depending on the year, notably we're in a crime surge at the moment.
While the number of gun deaths in the U.S. fell for the second consecutive year in 2023, it remained among the highest annual totals on record.
www.pewresearch.org
20k murders via guns in '21.
13 do 50 yada yada. there are 400+ million guns. 2,590 of gun murders were children and teens. And via the FBI's definition of active shooter, so not just school shooters, 104 died regardless of age. School shootings are %s of %s of %s of %s ect. The number of confounding variables, lack of agreed upon definitions, incomplete reporting, all make it a horribly difficult subject to comprehend. But a few things are clear, guns are not the problem in themselves. The media certainly carries a significant portion of blame:
The increase in giving children psych meds may be linked an
overall increase in violence. Those are just two confounding variables likely to be influencing the increase in these "school shootings."
ps this is me finding links and skimming pretty hard while drinking coffee