Why does Jonas feel apprehensive about the Ceremony of Twelve?

Jonas feels apprehensive about the Ceremony of Twelve in The Giver because it is the moment when the community will assign him the job he must do for the rest of his life, and he has no clear idea what that job will be.

His worry is sharper than his friends’ because most children have shown a strong interest in one kind of volunteer work and can guess their Assignments. Jonas has not had this experience. He has volunteered in many places rather than settling into one obvious path, so he cannot predict what the Committee of Elders will decide for him. In a community where people do not choose their own careers, that uncertainty matters deeply.

The ceremony also symbolically marks the end of childhood. Jonas’s father explains, “After Twelve, age isn't important. Most of us even lose track of how old we are as time passes.” During the ceremony itself, the Chief Elder tells each child, “Thank you for your childhood.” For Jonas, then, the event is a permanent turning point: his work, status, and daily life will all change, and even his friendships may shift as he begins spending time with people in the same Assignment.

His apprehension also comes from his sense that he is different. Jonas has pale eyes, has noticed the apple change in a way Asher could not see, and has not fit the usual pattern of children developing clear interests. In a society built around "Sameness" and careful rules, feeling different is unsettling. When the Chief Elder later skips Jonas's number at the ceremony, his private nervousness becomes public fear because he has been singled out in front of everyone.

Jonas’s apprehension grows from the pressure of a life being chosen for him and from his dim awareness that he does not fit neatly into the community’s expectations. That tension leads up to his selection as Receiver, the role that will separate him from ordinary community life completely.