What was the first world civilization in Mesopotamia?

Well, yes but their were numerous city states that arose individually in the pockets of the tigress and Euphrates's rivers.

And by the way it was Sumer probably

-history is only 72% factual-

The akkadians in incorrect. There was four major civilizations that started around the Tigress and Euphrates rivers. Summer is one of them, Then we have Egypt, then Indus civilization, and last Shang China. There were the four major civilizations. Later developed into city states as said above. Then even farther into the future and other civilizations start to rise and people start fighting.