Arle's "boku" pronoun

What was the team's approach regarding Arle's use of the boku pronoun? As far as I'm aware(which shouldn't say much), Japanese pronouns are more complex than English ones, leading to the question of how you approach the problem when translating.

Japanese pronouns are not that complicated to translate because English only has one option, “I”. As such the only thing to keep in mind is that the speech style conveys the same level of formality and/or level of egotism. There’s plenty of other sentence signifiers to help with this, ones that might override whatever extra information given by the pronoun. 

The only issues it poses is when the text specifically points out her personal pronoun as in Chronicle part 1— we can’t be literal and say “She refers to herself with ‘I’” because there is no other option in English. As such we just replace it with an adjective meant to convey the tomboyish tones of her personality.