Are 10 year olds allowed to watch Pretty Little Liars?

i wouldn't say 'kids' but preteens maybe. there is sex and drinking in the book and I think that some of the books contents may be too mature and wouldn't be understood as well by a kid verses someone in their teens reading the books I read the books when I was about 12 for the first time and now that I'm reading them again at 15 it all makes so much more sense to me