One's golden birthday, also called a champagne birthday, is the day when the age someone turns is the same as the day in the month he or she was born. For example, someone born on January 31st would celebrate his or her golden birthday when he or she turns 31. According to the Dictionary of American Regional English, this meaning is most prevalent in Wisconsin and eastern Minnesota, although it is used elsewhere. _Wikipedia
I'm from Wisconsin and today is my nephew Alexander's golden birthday.