Anime Watching anime characters that are in their teens and preteens talk about their dark and tragic pasts as a man in his mid thirties.

[Ikagura]

Oliver Twist took place in a modern high school with the girls wearing sailor uniforms?

No but the idea is still there: a character can still have an interesting backstory without the need to be old.

 

[redux007]

No but the idea is still there: a character can still have an interesting backstory without the need to be old.

In keeping with the fact that they're young and not an old person written as a child, yes. But, that is less of a background or past, and more of a present circumstance for them. That's my point. A child shouldn't sound like an old person. Even if the child is intentionally trying to affect that persona, it still wouldn't sound like an old person.