Brian Da Flyin Hawaiian 🌺

Yes. Calories matter.
Though, everyone is different, and our bodies will have different responses to seemingly similar circumstances.
With that said, I went from 100-300 calories the first 4 weeks to 300-500 the next couple months, to 500-750 up until month 7, when I started increasing calories because I wanted to STOP losing weight.
I did not go into "starvation mode" in the sense that likes to be discussed on this forum (I honestly think the way starvation mode is talked about on here is all sorts of wrong, but that is another topic altogether, and I digress...) So long as your body has fat (or other fuel) to burn, it will.
Like the smart people have said above, this early in the game, your focus should be on fluids and protein; you may not be perfect and hit it every single time, but get as close as you can comfortably.
Good Luck!