Number the Stars - how do annemarie's experiences in this section force her to grow up in a way that ellen is not yet forced to?

This depends on what section you are referring to. Do you have a chapter for this?

Annemarie is forced to grow up different from Ellen because Ellen is having to sneak away from the Germans to a safe place where she won't be killed or used for experiments in a concentration camp. But Annemarie doesn't have to worry about being killed or taken away because she is not a jew and she doesn't have a disability.