Why so mad about their age or at least their reactions? Yeah they reincarnated but they were just teenagers when they reincarnated and they never talked about their life was previously. So to die and then be re born into a life of hatred and abuse has gonna take its toll on the mind not to mention the back let their living with the emotions of 5 year old children
Not only that the way they describe their dead sounds like it implies that they took their own lives(in my opinion) so they might have gone through abuse or bulling in their pass, because they're so dismissal about it and is not like they have an advantage of having read about this new word in a book or having played a game or something.
Good thing the pictures are so obvious because the translation is horrible