You'll probably find that you will become more heavily invested in things that are incomplete; for example, Percy Jackson fangirls became much crazier and interested when Rick Riordan wrote a sequel series. Also, you'll find that a large percentage of the Harry Potter fans will be older. In fact, possibly the only reason why Lord of the Rings and The Hobbit are so popular with teenagers is because the movies were, until recently, unavailable. You will probably find that the percentage of teenage Tolkienerds will decrease within the next 5-7 years: a long time in the film and music industry. That reminds me; it's pretty much the same with music. Michael Jackson was incredibly popular with teens during his time; nowadays, while there are definitely still teenage MJ fans, there are nowhere near the amount that there used to be. It's a sombering, yet interesting thought. I'm also proud to say that speculation is entirely mine; I thought of it just now while eating a:

RICH
SMOOTH
CREAMY
MILK
CHOCOLATE
BALLS

chocolate from Woolworths.

Don't judge!!!