I don't recall any movie that any person under the age of even 18 is "allowed" to watched that has someone shooting someone else in the face repeatedly (or anything of the like). Kids aren't really supposed to be seeing that either. Kids watch Power Rangers, or Dragon Ball, or y'know all that good stuff. Yeah it has violence, but it's a very unrealistic violence that kids like to reenact with their friends just to play as their favourite badass characters.
I personally don't think kids should be exposed to sexual content. Nudity is one thing, but sexual content is another. I mean, I think I know of twelve 16-year-old girls that are preggo now. Why's that I wonder.
I wasn't being literal about the whole shooting someone else in the face repeatedly. Granted, I shouldn't exaggerate to make a point. I don't think brief sexual content or nudity is a big deal--As long as its not like a 10 minute sex scene or anything is it that big a deal? I saw a lot of 18+ movies as a kid (Like it started when I was around 8) And I don't think the scenes with nudity/sexual content messed with my head as much as the violence. I think I would rather have kids seeing nudity earlier on to get them comfortable with it, Then get comfortable with any type of fighting. Even if its just dragonball Z, it is
STILL GLORIFYING VIOLENCE Don't get me wrong I love DBZ for example, but you can't honestly tell me that watching guys kicking eachothers asses until one of them dies is a good thing