Started way too quick

I was just watching the movie and I see okk it's about two teens who might be in love ok ok...and than I was just 6 minutes into and aliens attack. Aliens......where the *beep* did the aliens come from............What's wrong with these people behind these movies.....don't they know anything about film structure and which scene should go first. I'm just 6 and half minutes into and I"m not going to continueee........I came to the imdb page to see if my consensus was the same and it was.