The film's
Anachronic Order, and
the ambiguity in the end of whether Jo really marries Friedrich or if only the fictionalized Jo in her book does, justifies the
Dawson Casting of the March sisters.
All the scenes that take place in the past represent Jo's memories and/or her book's fictionalized versions of those times. This is why all the sisters look like their "present" 20-something selves in the scenes of their teen years and in particular why Amy looks like a young adult when she's supposed to be a child. Those scenes aren't literal depictions of the past or of what the characters looked like – they're stylized recreations of those times from Jo's mind and pen.
- Of course Fridge Logic comes into play when you remember that there are several scenes where Jo is not present, meaning she couldn’t remember them.
- If they represent her book's narrative, then she could be just making those scenes up, either based on what the others have told her or by using her imagination.
- And what's more, if she wasn't there for them, then it makes even more sense why they'd look like their present selves - since she has to fit a face to a time she wasn't there for. And with no reliable access to photography, Jo has no way to remind herself of what they looked like back then.
