Uchida-san wa Zettai ni Gyaru Janai! - Ch. 4

[HYBRID_BEING]

She's confident only in the sense that she blindly acts without any situational awareness. The moment she stops to actually think about what she's doing, she immediately falls into self doubt. That's pretty much the opposite of a stereotypical gyaru, who know that they're cool and don't need to prove it to anyone.

I didn't see her falling into self doubt when together with MC, though. She tends to regress into her otaku personality due to habits, yeah (that doesn't seem to be a thing that irks him, though), and, as far as outward appearance goes, she acts confidently and cheerfully enough around him.