CORAL SPRINGS, Fla. — Cadet Peter Wang dreamed of attending the United States Military Academy at West Point one day, but he never got the chance. The 15-year-old was shot down last week at Marjory Stoneman Douglas High School as he held open a door so others could escape.

As he was laid to rest on Tuesday, West Point issued his family a ceremonial letter of acceptance. “One of U.S.M.A.’s priorities is to develop leaders of character who are committed to the values of duty, honor and country,” the academy wrote on Twitter. “Peter Wang’s actions on February 14 are an example of those principles, and the academy honors his dream of being a West Point cadet.”

The 17 people killed in the shooting rampage included three members of the school’s popular Junior Reserve Officers’ Training Corps: Mr. Wang, Martin Duque and Alaina Petty. Fellow students say the cadets acted valiantly, helping to usher others to safety. All three have been posthumously awarded the Medal of Heroism by the Army.

The accused gunman, Nikolas Cruz, 19, had also been a Junior R.O.T.C. cadet.

The corps is one of the high school’s largest clubs, with nearly 300 students who take courses in subjects like military drill, leadership and shooting. Their maroon polo shirts were a familiar sight around the school campus. Mr. Cruz may have counted on that. The police say he was wearing his maroon polo shirt when he was arrested, after having slipped away unnoticed after the rampage.