Also, quick note on the TL Note at the end:
Why is using your first name in Japanese seen as childish?
In Japanese, people hardly ever use the pronoun "you" in conversation, always using someone's name, instead, when talking to another person.
When kids are growing up, their parents address them by their names when asking them something, and they respond using the same, because that's how Japanese grammar works, and it becomes habit.
So in English when your mom asked you "Do you want something to eat?", you responded "I wanna eat!"
In Japanese (and I'm skipping over explaining some points of grammar here), the mother would ask "Hina will eat?" in a questioning tone, and Hina would respond with "Hina will eat!"
JP: Mother: "陽菜食べる?"
Hina: "陽菜食べる!"
This causes children to refer to themselves by their first names in the way that we would use "I" or "me", and you'll often hear girls especially continue to refer to themselves by their own name well into elementary school. The idea then becomes that girls that continue to do so into Middle and even High school are incredibly immature, since most girls stopped doing that when they were much younger.
The more you know~