I realized I am absolutely terrible at this game and actually can't beat the first boss in the... Uh... That one area after Atlas. Where you have to stay in the light or the Behemoths will get you? That first boss (reskin of an earlier one) is just... I can't beat it. Do I need to grind?

 

maybe I just need to git gud

If you can get a good sentinel like the Pulsework Knight (from the previous area), and just Tortoise quickly (3x SEN) every time he attacks, you can get pretty far. There is also a pretty good medic monster (the slug thing) you can get in the area you're in now. 

Also grinding does help.

Loved XIII-2, I even platinumed it.

Loved XIII-2, I even platinumed it.

NNNN why are you so good at these games ;-;

I personally went to the wrong world instead of the behemoth one by accident. I couldn't beat the a certain boss so I grinded like crazy, so by the time I found out I was supposed to go, I didn't even have to hide in the light.