La meva filla pregunta si podem trigar molt si anem al museu ara.

In Catalan, a possessive usually comes with a definite article:

• la meva filla = my daughter
• el meu cotxe = my car
• els nostres amics = our friends

That is different from English, where you normally say just my daughter without the.

So la meva filla is the normal standard pattern: article + possessive + noun.

They are related, but they do two different jobs here.

1. pregunta si podem...
   Here si means whether / if in an indirect yes-no question:

   • She asks if / whether we can...

2. si anem al museu ara
   Here si introduces a condition:

   • if we go to the museum now

So the sentence has:

• one si for an indirect question
• one si for a condition

Catalan uses the same word, si, for both.

Trigar means to take time, to be a long time, or to be delayed.

So trigar molt means to take a long time.

Examples:

• Trigarem molt? = Will we take a long time?
• He trigat dues hores. = I took two hours.
• Triga molt a arribar. = He takes a long time to arrive.

In your sentence, podem trigar molt means something like we may take a long time or it could take us a long time.

Poder means can / may / be able to.

So podem trigar molt literally means we can take a long time, but in natural English it often means:

• we might take a long time
• it could take us a long time

Here poder expresses possibility, not ability in the physical sense.

So the idea is:

• si anem al museu ara, podem trigar molt
  = if we go to the museum now, it may take us a long time

Catalan often leaves subject pronouns out because the verb ending already shows the person.

• podem = we can
• anem = we go

So nosaltres is unnecessary unless you want emphasis or contrast.

For example:

• Podem trigar molt. = We may take a long time.
• Nosaltres podem trigar molt, però ells no.
  = We may take a long time, but they may not.

This is very common in Catalan.

Because both parts call for the indicative here.

1. After preguntar si

When si means whether/if in an indirect yes-no question, Catalan normally uses the indicative:

• pregunta si podem...

2. In a real condition with si

When the condition is presented as a real possibility, Catalan also uses the indicative:

• si anem al museu ara...

So:

• si podem
• si anem

are both normal indicative forms here.

Because a + el contracts to al in Catalan.

• a + el = al
• de + el = del

So:

• anem al museu = we go to the museum
• not anem a el museu

This contraction is standard and required.

Ara means now. Here it belongs with anem al museu:

• si anem al museu ara = if we go to the museum now

Putting ara at the end is completely natural. It highlights the time condition.

You could also hear:

• si ara anem al museu

Both are possible, but si anem al museu ara is a very normal word order.

Yes. This is the standard way to introduce an indirect yes-no question.

Examples:

• Em pregunta si vinc. = She asks me if I’m coming.
• Pregunten si és obert. = They ask whether it is open.
• La meva filla pregunta si podem trigar molt...

So if English uses ask if or ask whether, Catalan very often uses preguntar si.

Yes, an English speaker may notice that repetition, but it is still perfectly grammatical in Catalan.

• pregunta si podem... = asks if/whether we can...
• si anem al museu ara = if we go to the museum now

Since each si has a different function, Catalan accepts this without a problem. Native speakers understand it easily from the structure.

So it may look repetitive, but it is normal.