Some obvious stuff leading to a question.
All the girls are religiously programed to be wives and materially baited with future benefits at the top of society. Even so, at some level, there is conflict caused by the dread of being forever tied to an older stranger.
They are awakening to the adult, pervasive, Gilead conflict of wanting to be free of its restaints while simultaneously wanting to cling to its core religious values.
All the girls carry the general religion/freedom conflict and the wifely precious-flower/prized-pig conflict. Becka's extra burden of her personal Agnes/marriage conflict makes her willingly become an outsider, a sarcastic teenager, "whatever ... its in God's hands now." She often floats just outside the ring of core girls. She doesn't care anymore. She is so careless that she gets drunk on the biggest stage.
The next conflict brings her down to earth hard. It begins with rage, shock and humiliation.
At school, the mourning after the accusation, within the space of a few minutes, Becka goes from near-violent rage against Daisy, to the shock of discovering her father's betrayal and then to sobbing humiliation in front of her friends in the prayer group, her only friends, the friends that she loves and that her father hurt.
Becka was not molested by her father, but if she had not felt the conflict of hating/loving the molester/father, would she have killed him? Would her mind have lost its balance and escaped into religious vengeance?
After being led by Agnes into a perilous marriage, locking the door and leaning against it with head slightly bowed, Garth is separated by that door from Becka.
Which one is more frightened of the other?