|Fionna||~ 5 ft & 10 in||~ 17 years old|
|Cake||~ 1 ft & 11 in||28 years old|
ANALYSIS OF ADVENTURE TIME: FIONNA AND CAKE MAIN CHARACTERS’ HEIGHTS
Firstly, we have to estimate Fionna’s height based on her appearance on Adventure Fandom Time since it was not stated yet on other websites. So, Fionna is an in-universe fictional character and the gender-swapped version of Finn who was created by the Ice King in his fan-fiction from a strange red glowing inspiration during Ice King’s sleep. However, she looks taller than Finn so, she is probably 5 feet and 10 inches tall.
Secondly, Cake is about 1/3 of the height of Fionna when he is in his size normally based on his photo on Wiki Fandom since there are times that he makes himself bigger than Fionna. But most of the time, he is shorter than Fionna. So, he probably is 1 foot and 11 inches tall.
ANALYSIS OF ADVENTURE TIME: FIONNA AND CAKE MAIN CHARACTERS’ AGES
Firstly, Fionna is estimated to be a teenager based on her characteristics in the TV Series. Moreover, she was described as very hard-headed as shown when Cake wanted her to date Prince Gumball and she was stubborn about it which is a characteristic of teenagers according to Adventure Fandom Time. So, she probably is 17 years old.
Adventure Fandom Time Fionna
Finn Adventure Time
Wiki Fandom Fionna and Cake