Help FFXIII: When do I stop taking Missions?

[Marius]

I just got to the worldmap, and I have done a couple of missions now, but they never stop. Theres always a new one to take. And now they are getting fucking hard. Do I just move on, or should I grind to get my level up?

These fights now are hard that one bad move kills the entire team.

Last mission I took was called 05 - Joyless reunion.
Enemy was Edimmu. Now this shit is just way too hard. Am I supposed to do all missions in this place before advancing further in the story?

 

[saajuk]

I just got to the worldmap, and I have done a couple of missions now, but they never stop. Theres always a new one to take. And now they are getting fucking hard. Do I just move on, or should I grind to get my level up?

These fights now are hard that one bad move kills the entire team.

Theres 64 missions total and only 21-26 are required to advance through the story. Id just complete story mode and then go after the missions. alot more options available to you and youll have a stronger party.

 

[Bambi]

I completed like, 3 missions and I still beat the story no problem, if you cant be arsed, just carry on. You can always g oback if you feel the need to train