From as early as they can understand. It should start from the very beginning.
Cyber-bullying is one form of trauma, but if we go into talking about sexual violence and all of those things, they all tie into each other one way or another. It's the culture that needs to be shifted, and at an age at which the boys and girls can understand. This could be kindergarten or grade 1. Bringing these in and simplifying it for them to be able to process the information would be very critical. To hear it when you're in grade 8 or grade 9 might be too late, since you've been told over and over when you were younger that this type of behaviour is okay. If you start from the younger age, then by the time you get to grade 9, that won't be an issue anymore.