This game isn't for a 11 year old kid. I am assuming you know its rated M already, but aside from the drug and conspiracy references, its really a game for a thinking person. Depending on how skilled your child is with gaming he/she might not be able to get very far in the game or understand the game much at all.
The games best offerings are in the story and the emails/ebooks you find and read in the game world to give you even more detail.
So in a nutshell I think there are better offerings you can give a 11 year old then Deus EX.