While taking their usual bath, the boys discuss how much Kyotaro is like an old man. The next day, when they go to school, they find themselves exhausted by climbing up the stairs... and learn that they're all becoming old men!
What, you don't mind the 
thought of getting older?
ماذا؟ لا تمانع فكرةَ أن تكبر؟
Ist es dir egal, ob du noch älter wirst?!
¿Qué? ¿No te importa envejecer más?
¿Qué? ¿No te importa envejecer más?
Ça ne te gêne pas
qu’on vieillisse davantage ?
Ti sta bene invecchiare così?
Como assim, você não se importa
  de pensar em ficar mais velho?
Погоди, ты хочешь постареть?