Cracking sound after screen protector installation on my iPhone

After I just installed my screen protector on my new Iphone, I pressed (a bit hardly) the middle of the screen with my 2 thumbs to make sure the protector sits perfectly and I heard a light but hearable crack. I checked for any bending or white spots on my screen but nothing visible. And i’m certain that the sound didn’t come from the protector.

I later also pressed the same spot a bit hard again to check if the sound would occur - and it did again. After the second time, I didn’t hear that sound again.

Should I be worried?

[Re-Titled by Moderator]