How old is Jack Frost from Rise of the Guardians?

How old is Jack Frost from Rise of the Guardians?

17 William Joyce has stated that Jack Frost was stuck at the age of 14, but is able to changed his physical age (up to a point) or become younger at will.. On the Rise of the Guardians App, it states: “”Jack Frost has been around for over 300 years, but he is forever trapped at the age of 17.””