Should I be worried

No. That's bad but not worryingly awful yet. It's just long past time to clean.

>>58974120
But I assembled it last December
I honestly have no idea why is there so much dust.

>>58974120
this

there's "dusty", you're past that
then there's "dust everywhere but still functional", you're about here
then there's "dust caked on everything, why isn't it on fire yet", not quite there yet
then there's "indoor smoker tier, oh god what the fuck", don't let it come to this

see how you can still see the gaps between the heatsink fins from the top? that's how you know it's not quite "too bad" yet, but you should give it a clean up anyway

>>58974100
Not really. The cpu will shut itself down before cooking itself.

That said, it would be wise to blow it out with compressed air for the sake of maintaining your things.

>>58974100
It's time to sort out your air circulation.

You should have more intake than output fans, so that the intake fans can sit behind at least a basic dust filter and keep dust from creeping in through cracks.