Ophelia was upset about the loss of trust and control, because Sterling escalated things faster then she was prepared to go. She was and still is interested in having a more sexual relationship with him, but the taboo is clearly a greater obstacle for her than for Brenna or Catherine, to the point were Sterling literally forcing the issue may have been the only plausible way to move forward.
Roleplaying the dom fantasy actually serves a dual purpose of letting her regain a feeling of control while also advancing to more sexual milestones. She's also clearly just having fun with it, framing cunnilingus as some sort of punishment when Sterling was more than willing to do it anyway, and he's clearly happy to go along with the roleplaying.
As mentioned many times in the thread, Ophelia expressed interest early on in exploring being dominant, but once that curiosity is satisfied I don't think we'll see any "hardcore" femdom. That actually would be too far out of character for her.