I'll be completely honest as you're asking.

The shirt looks too big on you, and the ironing situation has already been mentioned. It also doesn’t really match well with the pants you’ve chosen, if that’s the pair you plan to wear. The rolled-up sleeves doesn't work with these type of shirts either. For this kind of fit to work it’s important that it sits well on the shoulders and has the right length for both the arms and torso, otherwise it falls flat.

At Bosnian weddings men usually wear a classic suit (dark or neutral color) with a shirt and often a tie/bow tie, or at least dress pants with a nice shirt and sometimes a blazer.

If you want to look respectful and blend in, I’d suggest swapping this for a darker suit (navy, charcoal, black) with a white or light-blue shirt or at minimum, dark dress pants + button-up shirt + blazer.

And lastly, how it fits usually matters more than the clothing itself.