Batman is a fictional character that was created by artist Bob Kane and writer Bill Finger, and first appeared in Detective Comics #27 in May 1939. The character has since become one of the most iconic and recognizable superheroes in popular culture, appearing in comic books, television shows, movies, and other forms of media for over 80 years.

Despite his longevity, the age of Batman has been a subject of much debate and speculation over the years. In the comics, the character’s age has been adjusted and retconned multiple times to fit the changing narrative and keep the character relevant to contemporary audiences.
When Batman was first introduced in 1939, he was portrayed as a young, wealthy playboy named Bruce Wayne who witnessed his parents’ murder and became obsessed with avenging their deaths by fighting crime as a masked vigilante. At the time, he was depicted as being in his early 30s, which was considered middle-aged at the time.
In the years that followed, the age of Batman was adjusted to fit the changing narrative of the comics. During the Silver Age of comics in the 1950s and 1960s, the character was depicted as being perpetually in his late 20s or early 30s. In the 1970s and 1980s, the character was aged up to be in his 40s or early 50s, which allowed for more mature storylines and themes.
In the 1990s, the character was once again aged down to be in his late 20s or early 30s, which coincided with the popular Batman: The Animated Series and the subsequent Batman films starring Michael Keaton and Val Kilmer. During this time, the character was depicted as being at the height of his physical and mental abilities, with a sharp mind and a keen sense of justice.
In the early 2000s, the age of Batman was once again adjusted to fit the changing narrative of the comics. During the “Batman: Hush” storyline, which ran from 2002 to 2003, the character was depicted as being in his early 30s, which was consistent with his portrayal in the popular Batman: The Animated Series.
Since then, the age of Batman has remained somewhat ambiguous in the comics. While there have been hints and references to his age, such as his 80th birthday celebration in 2019, the character is generally portrayed as being in his prime, with no specific age given. This allows for greater flexibility in storytelling and allows the character to remain relevant to contemporary audiences.
In conclusion, the age of Batman has been adjusted and retconned multiple times throughout his 80-year history to fit the changing narrative of the comics. While he was initially depicted as being in his early 30s, his age has varied depending on the era and the needs of the story. In recent years, the age of Batman has been left somewhat ambiguous to allow for greater flexibility in storytelling.