High school seniors Emma Ehrens and Grace Fischer will hear their names read out today as they are called to collect their diplomas and start the next chapter of their lives. But they are also steeling themselves to hear 20 other names of former classmates who never got to leave first grade, let alone plan for college and grow into adulthood. Today is the day that the 20 children massacred at Sandy Hook Elementary School in December 2012 would have graduated, perhaps cheered on by the six teachers and administrators also killed in the deadliest K-12 shooting in US history. “It’s just going to be heartbreaking,” Grace told CNN. “I can’t imagine that 20 kids are not graduating with us and that they’re not having the opportunity to walk across the stage.”