Na de kapper valt Sofies pony mooi opzij, en ze glimlacht in de spiegel.

Literally, it is after the hairdresser, but in natural English it usually means after going to the hairdresser or after a trip to the hairdresser’s.

Dutch often uses this kind of short expression instead of a fuller version like na een bezoek aan de kapper or nadat ze bij de kapper is geweest.

Because naar de kapper means to the hairdresser and is used with movement:

• Ze gaat naar de kapper. = She is going to the hairdresser.

But after na you need a noun phrase meaning after the hairdresser / after the hairdresser visit:

• Na de kapper... = After the hairdresser / after going to the hairdresser

So naar would not fit after na here.

This is because Dutch main clauses normally follow the verb-second rule.

The first slot is taken by Na de kapper, so the finite verb valt must come next:

• Na de kapper = first position
• valt = second position
• Sofies pony = subject

So the structure is normal Dutch word order.

If you did not start with Na de kapper, you could say:

• Sofies pony valt mooi opzij.

Right. In this sentence, pony means fringe or bangs, not a small horse.

So Sofies pony means Sofie’s fringe/bangs.

This is a very common Dutch word in hair-related contexts.

Dutch usually forms possession by adding -s:

• Jans fiets = Jan’s bike
• Maries tas = Marie’s bag
• Sofies pony = Sofie’s fringe

An apostrophe is only added when Dutch spelling needs it, especially after certain final vowel letters, as in Anna’s or oma’s. With Sofie, Sofies is a normal possessive form.

Because mooi is acting as an adverb here, not as an adjective directly describing the noun.

It describes how the fringe falls:

• valt mooi opzij = falls nicely to the side

Compare:

• een mooie pony = a beautiful fringe
• de pony valt mooi opzij = the fringe falls nicely to the side

So no -e ending is used here.

Literally, vallen means to fall, and opzij means to the side or sideways.

With hair, Dutch often uses vallen to describe how hair naturally sits or drops. So here:

• valt mooi opzij

means something like:

• falls nicely to one side
• sweeps nicely to the side
• lies nicely to the side

It sounds very natural in Dutch when talking about hair.

Because opzij is an adverbial element showing direction or position, and in Dutch those often come later in the clause.

So:

• valt mooi opzij

is a normal order.

Dutch often keeps the finite verb early in the sentence and places words like opzij, naar buiten, omhoog, beneden, etc. later.

It refers to Sofie.

So the second clause means:

• and she smiles in the mirror

It does not refer to pony. In context, the person smiling is clearly Sofie.

Yes, literally it is in the mirror, and that is also natural in English.

It means that she sees herself there and smiles at her reflection. So:

• ze glimlacht in de spiegel

means:

• she smiles in the mirror
• she smiles at herself in the mirror

Both capture the idea well.