You will probably have the easiest time answering this question if you examine the character of Meg. The book centers mostly on her, and her character is the most developed in the story. She is also a complex person. From the start of the story, Meg is shown to be impatient, impulsive, moody, irascible, and lacking in self-confidence. However, we see her overcome these characteristics and even use them to her advantage as the story progresses.
Indeed, Meg has many conflicting feelings about herself that you can use when answering this question. She has strong feelings about just about everything and everyone but is hard on herself for her own emotionality. As Meg says in chapter 1 (page 12 in my edition), "I hate being an oddball." But as her mother tells her, "You're much too straightforward to pretend to be what you aren't." Throughout the story, Meg gradually comes to accept and embrace her oddball ways. In the end, it is her strong feelings that allow her to save her brother.
Meg also has very conflicting feelings about her father. She loves and misses him dearly during his long absence. She will do anything to find him. However, when they finally are reunited, she is terribly angry at him and refuses to forgive him for his perceived abandonment of the family. Meg also blames him for leaving Charles Wallace on Camazotz even though she also understands, albeit subconsciously, that her father made the only choice he could at the time. Meg still loves her father, of course, but only expresses resentment towards him after their reunion. Indeed, when her father explains why they left her brother behind, she responds harshly to him:
"You shouldn't have tried to tesser, then." She had never spoken to her father in this way before. The words hardly seemed to be hers. (chapter 10, page 164)
I suggest that you re-read the last half of chapter 10 and look at all the ways in which Meg lets her emotions get the better of her. She is angry at her companions even though she understands at a deeper level that they did what was best. Then you can look at Meg's resolve in the final chapter when she seems to forgive herself for her earlier harsh feelings and, despite her many fears, finds the courage to put herself in harm's way to return to Camazotz to save her little brother.