@Kaarme Everything that happened right here can be summed up in one sentence: kids/teens are stupid hormonal monsters.
She loves her dad, but the fact that he exploded on her the moment he saw her (even if for a good reason) set her off cause she's a kid and kids are immature like that. It's like "While I'm out here spending my precious time finding you a present, you treat me this way?" She wasn't being tsundere. She inadvertently took an attitude because her dad got mad at her for something that should have been a positive thing (even if he's unaware) and turned it into a fight.
If she had better control over her emotions (something obviously notoriously difficult for teens), she would have just told him the truth instead of turning it into a fight.
Edit: I mean for real though the author could have intended for her to just be embarrassed by the reason like
@manabi mentioned, leading to her rebellious attitude. It wouldn't be a first in anime or manga. Depending on how openly friendly she is with her father, it might be embarrassing for her to obsess over a gift for him.