In season 1 bad dreams vanessa was complaining about her being too young to see scary movies but she was around 11 or 12, there are kids 5 years old watching horror movies nowadays, do you think cliff and clair should have just let vanessa see the horror movie without her sneaking in to see the movie ???



https://www.youtube.com/watch?v=n3eJkf4erbI
https://www.youtube.com/watch?v=n3eJkf4erbI
https://www.youtube.com/watch?v=n3eJkf4erbI
https://www.youtube.com/watch?v=n3eJkf4erbI

Depends on the child, depends on the horror movie. Some kids can deal with scary things earlier than others, it's totally up to the parents' discretion. If the child is having nightmares from it then yeah they might be too young.
There were kids when I was 5 seeing horror movies, including me (that was 1975), but that has zero bearing on whether Vanessa should see one or not at her age.