QUINCY — Lamar Thompson loved soccer and was hoping to score a lot of goals for the Quincy High School team this fall. Jamaican dancehall was his favorite music, especially the artist Vybz Kartel. He liked cooking traditional Jamaican dishes such as stewed chicken, rice, and peas — and scrambled eggs, the favorite of his 9-year-old sister Tashia.

Those were just some of the memories that friends and family shared as more than 100 gathered at Quincy High School Monday night to mourn Thompson, 18, who drowned Sunday afternoon after jumping off a pier at the Quincy Yacht Club.

Mark Thompson said his son “was not really a big swimmer” and usually did not go ­into water over his head. It surprised him that Lamar would dive into water that he said is about 18 feet deep.

The father said he is trying to surround himself with family and friends right now, because being alone is too depressing. It is difficult for him to accept that his son is gone. “I don’t understand why so soon, at that tender age,” he said.

The loss of the young man who had just completed his ­junior year had some students reflecting outside the memorial on how unexpectedly a life can end. “It’s just crazy, how one minute he’s gone,” said Alexis Monfiston, 17. “It’s not like he went to the beach knowing he was going to die. He just wanted to have a good time.”

Thompson grew up with his mother in Kingston, Jamaica, and came to live with his father and stepmother in Quincy last fall. In a short time, he ­impressed many classmates and teachers.

“He not only was a kid who was always smiling and joking, but he was a hard worker who never missed homework and was an extremely positive presence in class,” said Chris ­Natalizia, 31, Thompson’s honors English teacher.

Scifo Campbell, 17, said he and Thompson were “the best of friends.” They bonded over their Jamaican upbringings and love of dancehall music, Campbell said, wiping tears from his eyes as he sat outside the memorial.

“I hate the feeling,” Campbell said when asked about his grief. “It heals, but it’s going to take a while.”

Taliyah Rodriguez, 16, sat with Campbell, gently rubbing his back in consolation. She said Thompson loved Jamaica, but had come to love ­Quincy High during his time there.

Bai Kanu, 18, played on the soccer team with Thompson. Kanu, an immigrant from ­Sierra Leone, said Thompson loved books and impressed him by reading “A Long Way Gone: Memoirs of a Boy Soldier,” ­Ishmael Beah’s book about the civil war in the West African ­nation.

The friends last spoke on Sunday, about an hour before the leap into the water that led to Thompson’s death. Around 4 p.m., Kanu ran into a mutual friend who said Thompson had drowned. “I didn’t believe the whole thing,” Kanu said. “I still don’t believe it.”

Kanu recalled Thompson predicting he would score lots of goals in soccer this fall. He hopes he can wear Thompson’s jersey to keep his legacy alive.

“And I will make sure I score a goal for him,” he said.