In her senior year, she saw the navy recruiting ad again, couldn't resist this time and signed up. She finally got the support from family and teachers and joined the navy in 2015.

She wanted to be a member of the Marine Corps, so she crafted a rigorous training plan. She spent more time than other soldiers on every subject, including a 5 kilometer cross country race, barbed wire climb and shooting.

In December 2015, she was enrolled into the Marine Corps with the top score, becoming an amphibian scout. She was also Peking University's first marine.

At the end of 2016, she set off with the 25th Chinese navy fleet to carry out escort missions in the Gulf of Aden and Somalia as the only female marine. The fleet carried out 62 escort missions, rescued two ships and drove away boats of suspected pirates 82 times.

In December 2017, she retired from the military and went back to college to continue her studies.

"Though I've finished, I still long to go back into the military," Song said. "I want to enroll again when I finish my post-graduate studies."