Birthday party problems/how age aptopite is G.I. Joe?

Well my birthday is coming up and there are 2 movies that come out in time for my birthday. Coraline and G.I. Joe. I am planing on seeing 1 for my birthday party. Since me and my friends all love the book coraline I thought that we should all see coraline for my birthday party (seeing as it comes out on the same week as my birthday). But 2 of my friends say that there not going to come to my party because they think (or as they say know) that coraline will suk and will be the biggest piece of sh** this century. So that leaves only 1 friend of mine is going to see the movie. So I thought that we could see G I Joe instead. But G I Joe is rated M and last year one of my friends couldn't go to my party because his mum wouldn't let him see The Dark Knight. And I thought that the same thing would happen with G I Joe. And well movies usually come out later in New Zealand than they do in America so I thought that G I Joe has probably come out already in America. So if it has can you tell me if it would be suitable if his mum didn't let him see The Dark Knight?