Luckily, school aged kids and young adults are not particularly susceptible to this disease. Some older teachers might be however. We as a society seem to be over-reacting. Go about your day, and do everybody a favor and self-quarantine if you get sick. No need to close schools if people follow simple rules (which they probably won't.)
it's good that those age groups are better able to withstand infections of Covid-19. But they can certainly carry it home to infect older relatives and others in their neighborhoods. It's not too much to expect younger people to take precautions to protect their grandparent's health. For them to go about their day ignoring social distancing and not wearing masks is very selfish.