User blog comment:Adventuretimegurl123/OH MY!! HUGE ADVENTURE TIME NEWS!! :D/@comment-121.217.89.112-20130513065503/@comment-66.26.115.209-20130523013804

Actually PB is like 100 years old she doesn't age past 18. It did state in an episode she can not live forever, but if you look at her wiki shes over one hundred years old, but appears 18.