User blog comment:Adventuretimegenghiskhan/How Old Is PB?/@comment-24241745-20140129061601

she is 18 because in the episode of too young the earl of lemongrab becomes king when princess bublegum was 13. This episode ended with her recovering her candy biomass by smoching with finn and turning 18,to be able to rule and take out lemongrab. Think it like if she was Marceline, she haves a body of an 18 year old but is about maybe more than 300 years old, could 1000 years old.