Well, yes.
“The new Division of Criminal Justice numbers from last school year show 368 total incidents of all types at elementary schools, with 13 percent involving marijuana. At middle schools, 18 percent of the total 1,809 incidents involved pot, as did 30 percent of the total 4,118 incidents at high schools.”
...so yes. They ARE starting much sooner.
What are the other 87%?
From your link:
there was no statistical change pre- and post-2014,” Kreminski said.
Student attitudes have remained the same before and after legalization in terms of how harmful students perceive the use of marijuana to be and how wrong they think cannabis use is, Kreminski said.