“She was the kind of kid that when you made her smile,” he said, “it felt like a real win.”

After graduating in 2015, her mother said, Ms. Goodson had big dreams. She worked for about a year at a day care center in Stamford, and loved it. But she had also talked about becoming a security guard or a flight attendant.

Ms. Goodson’s daughter was the light of her life, her cousin, Ronshuana Anthony, said.

“Malaysia just gave so much of her self,” Ms. Anthony said, adding, “She’d give her last breath to her if she could.”

When emergency responders arrived at the subway station on Monday night, Ms. Goodson was unconscious and unresponsive, police said.

She was taken to the Mount Sinai West hospital, where she was pronounced dead.

Ms. Goodson’s daughter was found conscious and treated at the scene. She was reunited with her father and grandmother in the city and was doing well, Tamika Goodson said.

It was not clear whether Ms. Goodson suffered a medical condition or if she was killed from the impact of the fall. The city’s medical examiner will determine her cause of death, officials said.

Shams Tarek, a spokesman for the Metropolitan Transportation Authority, which operates the subway, called the death “a heartbreaking tragedy” and said the agency would work with the police to investigate.

While officials are continuing to probe the circumstances around Ms. Goodson’s fall, her death has shined a light on the lack of elevator service and accessibility issues that have long plagued the city’s subway system.