I can assure you, these trends are not reflected at my school.
Why is her assertion of trends more valuable than mine or anyone else's? Why does her school better exemplify our cohort than mine or anyone else's?
One conversation does not constitute a definitive explanation for the social media use of a generation. Use changes based on location, income, race and gender balance, ect. in schools.
This is a complex topic. One anecdote can't offer any real insight.