They’ve done it. Upper Valley high school seniors have earned their diplomas — some with flying colors, others just barely, with fingers crossed nearly to the end. The graduates have bid farewell to high school, and in a way, childhood, marching off after listening to advice from elders — an increasingly rare occurrence.

Graduates may be too swept up in the moment to contemplate the meaning of recent events, which honored them individually, and the entire graduating class as well. In those last hours, the class may have found a sense of unity that eluded them ever since academic grades separated the best from the rest and coaches separated the promising from the bench-warmers. At graduation, there is something stirring about seeing seniors in their gowns, looking more alike than not, the uniformity a departure from the dizzyingly varied teen fashions that celebrate the individual — almost to a fault these days.

In New Hampshire, the Legislature faced questions about graduation tradition when it voted this year to allow students who’d completed boot camp during the previous summer to wear military dress uniforms to their graduation ceremonies. Gov. Maggie Hassan signed the bill in May. School administrators who’d resisted the practice pointed to the long tradition that held that the commonality of graduates was most important, but the story of Marine Lance Cpl. Brandon J. Garabrant changed hearts and minds. He died in June 2014, when the tank he was riding in was hit by a roadside bomb in Afghanistan. A year earlier, administrators at ConVal Regional High School in Peterborough, N.H., had denied his request to wear his Marine uniform at graduation ceremonies, raising objections across the nation.

Although we value the tradition and symbolism of graduation gowns, the times dictate that schools allow this exception so as to avoid any expression of disrespect, however unintended, toward military service. For years now, this country has asked much of young people who enlist. They have taken a step toward a possibly dangerous future; more than their peers, they have entered the adult world of decisions and commitment, which the uniform symbolizes.

Traditions change, albeit slowly. At Hanover High, all graduates wear maroon gowns, not white for girls and a color for boys, as happens at most graduations. “It doesn’t seem necessary, to me, to separate graduates by gender. The graduation ceremony is designed to recognize the academic achievements of the class,” Principal Justin Campbell explained. Given the compelling case for gender equality, and now, new understandings about gender identity, there may soon be a call for wider adoption of Hanover’s practice. Better to begin the discussion sooner than face hurtful controversy later.

Even as graduation speakers urge students to change the world, the world is changing all around them — the young take it in stride, and adults are left to catch up.