Princess Aiko, the only child of Emperor Naruhito and Empress Masako, turned 18 on Sunday, enjoying her last year in high school as she prepares to move on for further studies at university starting next spring.

The cello-loving princess, currently a third-year student at Gakushuin Girls' Senior High School in Tokyo, vigorously carried out school assignments and studied for exams -- sometimes getting advice from the imperial couple, according to the Imperial Household Agency.

The princess rejoiced in her class victory at an athletics meet in September, while spectators were excited when she performed dance at a school festival in November, the agency said.

However, the agency's Board of Chamberlains declined to comment on which university the princess is considering attending.

During her trip to Tochigi Prefecture, eastern Japan, with her parents in August, the princess talked to a local female student of the same grade and they encouraged each other on their studies.