Final answer:
Rachel wished she wasn't Eleven because it (b) represented an awkward stage between childhood and adolescence where she felt the expectations to be more mature yet still experienced feelings of being a child.
Step-by-step explanation:
Rachel wished she was anything but Eleven because the age eleven for her was a mix of feeling not quite grown up and still being considered a child. This is a common theme in the coming-of-age story "Eleven" by Sandra Cisneros.
Being eleven is portrayed as confusing and uncomfortable since Rachel still experiences the vulnerability and helplessness of being younger, even on her eleventh birthday, when she is expected to be more mature.