Ako si spremna, uzmi svoju torbu i idemo.

Because spremna is the feminine singular form of the adjective spreman / spremna / spremno meaning ready.

In this sentence, the speaker is talking to one female person, so the adjective has to agree with that person.

• Ako si spremna = If you are ready (said to a woman)
• Ako si spreman = the same thing, but said to a man

Agreement like this is very important in Serbian.

Serbian often drops subject pronouns when they are already clear from the verb form.

Here, si already tells you the subject is you singular, so ti does not need to be stated.

• Ako si spremna = If you are ready
• Ako ti si spremna is not correct standard word order

If you do include ti, it is usually for emphasis or contrast:

• Ako si ti spremna... = If you are the one who is ready...

Because si is a clitic, and Serbian clitics usually go in the second position in their clause.

In Ako si spremna:

• Ako is the first element
• si comes right after it

This is normal Serbian word order.

So:

• Ako si spremna = natural
• Ako spremna si = not natural in standard Serbian

This second-position rule is something learners see a lot with forms like sam, si, je, smo, ste, su, as well as short pronouns.

Uzmi is the imperative form meaning take.

It comes from the verb uzeti = to take.

So:

• uzmi = take! (to one person)
• uzmite = take! (to more than one person, or formal singular)

In this sentence, the speaker is telling one person to take the bag:

• uzmi svoju torbu = take your bag

Serbian usually uses svoj when the possessor is the same as the subject of the clause.

Here, the implied subject is you, and the bag also belongs to you, so svoju torbu is the most natural choice.

• Uzmi svoju torbu = Take your own bag
• Uzmi tvoju torbu is possible in some contexts, but it often sounds less natural unless you are emphasizing your as opposed to someone else’s

This is one of the most important uses of svoj in Serbian.

Because torbu is in the accusative case.

The verb uzmi takes a direct object, and direct objects often go in the accusative.

• torba = nominative
• torbu = accusative

So:

• torba = a bag / the bag as the subject
• uzmi torbu = take the bag as the object

This is a very common pattern in Serbian.

Yes, literally idemo is we go / we are going, but in context it often works like let’s go.

Serbian commonly uses the 1st person plural present tense to suggest doing something together.

So here:

• idemo = let’s go

It sounds natural and conversational. A speaker is basically saying:

• Take your bag, and let’s go

You may also hear:

• Hajdemo!
• Hajde da idemo!

But idemo by itself is extremely common.

Yes. Ako is the normal word for if in a real condition.

• Ako si spremna... = If you’re ready...

It introduces a condition before the command that follows.

This is a very common pattern:

• Ako imaš vremena, dođi. = If you have time, come.
• Ako si gladna, jedi. = If you’re hungry, eat.

Because Ako si spremna is an introductory conditional clause, and it is separated from the main clause by a comma.

Structure:

• Ako si spremna = dependent clause
• uzmi svoju torbu i idemo = main clause

So the comma marks the break between:

• If you’re ready,
• take your bag and let’s go.

That punctuation is standard.

Yes, but one word would need to change.

To a man, you would say:

• Ako si spreman, uzmi svoju torbu i idemo.

Only the adjective changes to match the gender of the person being addressed.

Everything else can stay the same.

It is informal singular, because the speaker is addressing one person with the ti form.

Clues:

• si = you are for ti
• uzmi = singular informal imperative

If you were speaking formally to one person, or to multiple people, you would use:

• Ako ste spremni, uzmite svoju torbu i idemo.

Depending on who is being addressed, the adjective may also change for gender/number.

Some parts can move, but the given version is very natural and standard.

• Ako si spremna, uzmi svoju torbu i idemo.

This order sounds smooth because it gives:

1. the condition
2. the command
3. the invitation/action together

You might hear variations in speech, but beginners should treat this version as a very good model. The main thing to be careful about is keeping clitics like si in the correct position.