I am doing a persuasive speech on gun control. What key points should I include?

An armed society is a safe society. Proven fact. Why hasn't the University of Utah had a school shooting and Virginia Tech, Columbine, and plenty more have? Why is it when there's more gun control there's more crime and gun violence? Imagine the University of Utah..where students are allowed to carry a firearm..and never had a shooting...but on a larger scale...say the United States of America...All American citizens with a clean violent criminal background record were allowed to carry (concealed or open carry) firearms without the need of a permit to do so. A robber would think twice about robbing that convenient store if the clerk and all the customers inside and outside were armed. I believe this would cause gun violence and all crimes to plummet to a national record low. And the only people who suffer from gun seizures should be violent felons and gang members.