Imam pet godina radnog iskustva.

Because Croatian uses the verb imati = to have for this kind of idea.

So Imam pet godina radnog iskustva is literally structured as:

• Imam = I have
• pet godina = five years
• radnog iskustva = of work experience

This is the normal Croatian way to say that someone has a certain amount of experience.

Yes. That is one thing that often surprises English speakers.

In Croatian, age is expressed with imati = to have, not with biti = to be.

So:

• Imam pet godina. = I am five years old.
• Imam pet godina radnog iskustva. = I have five years of work experience.

The extra words radnog iskustva make it clear that this sentence is about experience, not age.

Because after numbers 5 and higher, Croatian normally uses the genitive plural form of the noun.

So with godina:

• jedna godina
• dvije godine
• tri godine
• četiri godine
• pet godina
• šest godina
• deset godina

That is why the sentence has pet godina.

Because iskustva here is the genitive singular of iskustvo.

The phrase works like five years of experience. After a measure expression such as pet godina, Croatian often puts the thing being measured in the genitive:

• pet godina iskustva
• deset litara vode
• puno vremena

Also, iskustvo is usually treated as a mass noun here, so singular iskustva is natural: experience, not experiences.

Because the adjective has to agree with the noun it describes.

The base form is:

• radno iskustvo = work experience

But in this sentence, iskustvo becomes iskustva because it is in the genitive singular. So the adjective must also change to genitive singular neuter:

• radno iskustvo
• radnog iskustva

So:

• radnog matches iskustva

Good question. The whole phrase pet godina radnog iskustva functions as the object of imam, but inside that phrase, numerals and measure expressions affect the forms of the words.

So:

• imam still has an object
• but pet causes godina
• and godina as a measure word leads to iskustva

So the sentence is completely normal even though several words are not in a simple accusative form.

Yes, absolutely.

• Imam pet godina iskustva. = I have five years of experience.
• Imam pet godina radnog iskustva. = I have five years of work experience.

Adding radnog makes it more specific and professional. Without it, the meaning is broader, though in a job context people will often still understand it as work experience.

The form of godina changes with the number.

Examples:

• Imam jednu godinu radnog iskustva.
• Imam dvije godine radnog iskustva.
• Imam tri godine radnog iskustva.
• Imam četiri godine radnog iskustva.
• Imam pet godina radnog iskustva.

So the big pattern is:

• 1 → godinu
• 2, 3, 4 → godine
• 5+ → godina

Yes, Croatian word order is fairly flexible, but this version is the most neutral and natural:

• Imam pet godina radnog iskustva.

Other orders are possible, but they sound more marked, contrastive, or stylistically special. For example:

• Pet godina radnog iskustva imam.
• Radnog iskustva imam pet godina.

Those are not impossible, but for normal conversation, job applications, or textbook usage, the original order is best.

Yes, very natural.

In speech, you can say the full sentence:

• Imam pet godina radnog iskustva.

On a CV, people often shorten it and leave out the verb:

• Pet godina radnog iskustva
• 5 godina radnog iskustva

So the full sentence is perfect in conversation, and the shortened version is common in written professional contexts.

Yes. Radnog and radnoga are both possible genitive singular forms in standard Croatian.

• radnog iskustva
• radnoga iskustva

In everyday use, radnog iskustva is more common and more neutral. Radnoga iskustva can sound a bit more formal or stylistically heavier.