Why does Jonas feel like his childhood is slipping away from him?

Jonas feels like his childhood is slipping away because he is beginning to experience the complexities and responsibilities of adulthood as he undergoes the Ceremony of Twelve, where he is assigned his life’s role. The increasing awareness of emotions, memories, and the weight of choices contrasts sharply with the simplicity and innocence of his earlier years. Additionally, his exposure to the darker realities of his community through his training as the Receiver of Memory further emphasizes this loss of childhood innocence.