That’s because HE STILL HAS THE MINDSET OF A TEEN/CHILD BECAUSE HE DIED AT SUCH A YOUNG AGE AND ALL HE KNOWS IS TO HAVE FUN AND PROTECT THE ONES HE LOVES NO MATTER WHAT
mmm i personally headcanon my jack as 18 ( sorry joyce ) but like here . think about it this way , it’s not your age that makes you you , it’s what you’ve gone through , your experiences , that makes you who you are . considering the facts that ( 1 ) jack’s been wiped of his memories , ( 2 ) he’s had no one to guide him in 300 years , ( 3 ) how he wasn’t able to develop his attitude properly even in his human years , pre guardian jack is grossly without much responsibility in his body . it’s why his conversations with the guardians about their centers are important : it all gave him insight of what he’s seen & gone through for the past 300 years .








