Crown Princess Masako, who turned 55 on Sunday, vowed to make her best effort to serve the people as she is set to become Empress following May’s Imperial succession.

“I want to devote myself to the happiness of the people so I will make an effort to that end while gaining more experience,” the Crown Princess, who has long been battling a stress-induced illness, said in a statement.

In the statement released by the Imperial Household Agency, the Crown Princess said she is “filled with deep emotions and feels nostalgic” about her birthday this year being the last one in the current Heisei era.

The era will end after Emperor Akihito, 84, abdicates on April 30, the day before the enthronement of his eldest son, Crown Prince Naruhito, 58. The Emperor expressed his desire in August 2016 to step down due to his age and health.

The Crown Princess expressed her gratitude for the Emperor and Empress Michiko, noting that the Imperial Couple “warmly welcomed me and generously continued guiding and watching over us” since her marriage to the Crown Prince was decided about 26 years ago.

Referring to the Imperial Couple’s new life after the succession, the Crown Princess said, “I wish from the bottom of my heart (the Imperial Couple) will unwind from their busy life and spend peaceful days.”

The Harvard and Oxford-educated former diplomat has been struggling with adjustment disorder since December 2003, but she has shown signs of improvement.

This year, she attended a biannual Imperial garden party for the first time in 15 years.