Since I am 18, I may be in the young crowd.
I saw Alien when I was 5 or 6, except it was on a VHS tape (not DVD) like most things when I was young. Even though I didn't understand, I was still fascinated. The haunting imagery stayed with me until I was in my early teens and had a friend who owned the entire series, when I saw them.
But I don't think all young people should be put in the same thought box. I HATE AvP, and i barely like Predator. So there are some of us whippersnappers who do appreciate the logic behind all the violence.
And i am just going to say, I really envy those of you who were able to see those films on the big screen. Why can't they start showing the Alien films in theaters again instead of crap like Titanic?