Ponekad mislim da sam u pravu, ali tek kasnije shvatim drugu stranu priče.

Ponekad means sometimes.

It is quite flexible in the sentence. In your example, it comes first:

Ponekad mislim...

That sounds very natural. But Croatian word order is fairly flexible, so you could also hear things like:

• Mislim ponekad da sam u pravu...
• Tek kasnije ponekad shvatim...

Moving it usually changes emphasis more than meaning. Putting ponekad first is a very normal way to set the scene.

Croatian usually leaves out subject pronouns when they are not needed.

The verb endings already show who the subject is:

• mislim = I think
• shvatim = I realize / understand
• sam = I am

So ja is unnecessary unless you want extra emphasis or contrast.

For example:

• Ja mislim da sam u pravu, a ti ne. = I think I’m right, and you don’t.

In your sentence, leaving out ja is the most natural choice.

After verbs like misliti meaning to think, Croatian normally uses a da-clause:

• Mislim da... = I think that...

So:

• mislim da sam u pravu = I think that I am right

This is very common in Croatian. English can sometimes shorten this kind of structure, but Croatian generally prefers da + finite verb in these cases.

U pravu is a fixed expression meaning right in the sense of correct.

So:

• biti u pravu = to be right
• nisam u pravu = I’m not right / I’m wrong
• jesi u pravu = you are right

Literally, it is something like to be in the right, which is why English speakers often find it memorable.

Because u here requires the locative case in this expression.

The noun behind the expression is pravo, and in the locative singular it becomes pravu:

• pravo
• u pravu

So sam u pravu literally follows the pattern I am in the right.

Even if you do not analyze it every time, it is best learned as the set phrase biti u pravu.

Kasnije means later.

Tek adds the idea of only, not until, or only then.

So:

• kasnije = later
• tek kasnije = only later, not until later

That means the speaker does not understand the other side immediately. The realization comes afterward.

This is an important nuance in the sentence.

This is mainly about aspect.

• shvatiti is perfective
• shvaćati is imperfective

Shvatim presents the action as a completed insight: at some later point, I come to realize it.

That fits the sentence very well, because the speaker is talking about reaching a conclusion later.

So:

• tek kasnije shvatim = only later I realize / come to understand

If you used shvaćam, it would sound more like an ongoing process or general state of understanding. Here the point is the moment when the understanding finally happens.

Yes, perfective present often refers to the future, but it can also be used in habitual or repeated situations.

Here the adverb ponekad tells us this is something that happens from time to time. In each such situation, there is a completed moment of realization, so shvatim works well.

In other words, the sentence is not describing one single present moment. It describes a repeated pattern:

• Sometimes I think I’m right
• but only later I come to realize the other side

So the perfective verb is natural.

There are two different case relationships here.

1. drugu stranu

This is the direct object of shvatim, so it is in the accusative.

• nominative: druga strana
• accusative: drugu stranu

2. priče

This is in the genitive, because it depends on strana:

• strana priče = the side of the story

So the whole phrase literally means:

• the other side of the story

Because the adjective must agree with the noun in gender, number, and case.

The noun is strana, which is:

• feminine
• singular
• accusative here

So the adjective drugi changes accordingly:

• nominative feminine singular: druga
• accusative feminine singular: drugu

That is why you get:

• drugu stranu

Usually it is understood as the other side of the story.

In context, drugu stranu often means another perspective that the speaker did not appreciate at first. It is a very natural expression for seeing a situation from someone else’s point of view.

So even though drugu literally means second / other, the idiomatic sense is very close to the other side of the story.

Sometimes, but the nuance changes.

• razumjeti = to understand
• shvatiti = to realize, to grasp, to come to understand

In your sentence, shvatim is better because it suggests a later moment of insight. The speaker does not just understand in general; they suddenly or eventually realize the other perspective.

So shvatim is a very good choice here.

Yes, you could absolutely say:

• Ponekad mislim da sam u pravu, ali tek kasnije shvatim drugu stranu priče.
• Ponekad mislim da sam u pravu, ali shvatim drugu stranu priče tek kasnije.

Both are grammatical. The difference is mainly emphasis.

• tek kasnije shvatim puts focus on the delay
• shvatim ... tek kasnije also works, but places the timing later in the sentence

Croatian often allows this kind of movement more freely than English.

Because da sam u pravu is a closely connected subordinate clause that functions as the object of mislim.

So the structure is:

• mislim = main verb
• da sam u pravu = what I think

In normal Croatian punctuation, you usually do not put a comma before da in this kind of sentence.

So:

• Mislim da sam u pravu. ✅
• Mislim, da sam u pravu. ❌ in normal usage

It sounds very natural.

It has several features that are especially idiomatic in Croatian:

• ponekad for sometimes
• mislim da... for I think that...
• biti u pravu for to be right
• tek kasnije for only later
• shvatiti drugu stranu priče for understanding another perspective

So this is not just grammatical Croatian; it is also the kind of sentence a native speaker could easily say.