[ZrByte]

I gotta say it depends on the film. I was under 10 when I first saw Aliens, that film scared the crap outta me until I finally saw the end, now its one of my alltime favorite movie and has been since I was about 10, I also considder this to be more scifi than horror, same goes for terminator.
However, The first part of IT (steven king) still scares me today, dont know what it is about it but that film freaks me out no end. I actually find the second part quite funny though. 28 days later also freaked me out a bit, zombie movies have never bothered me because zombies are slow dumb and unmotivated, this freaked me out because they where fast and angry.
I was nearly crying with laughter when I first saw omen and the exorcist.

Age ratings really mean nothing, as has been said before it should be based on the person.