I want to say no, but as a wanna-be anime-style artist, I had to be a fan of anime/manga first. XD I never drew too many pictures of characters from shows or books that I liked but I did try to mimic styles from them. Example: I drew many of my OCs/ fan characters in the style for that world, but I never drew the characters from the original story.
How else are you going to learn? Well yeah I know their are zillions of ways but like the old adage says, "Mimicry is the highest form of flattery" and is excellent practice to toning your artistic chops.
Fan art is a great way to start! If you focus on something you like, you'll put more effort in to it. In turn, that extra zeal you had will increase the amount your talent increases, so you can draw good even if you don't like your drawing.
I would have to say yes, considering that the majority of art that I did before fan art consisted of disturbing monsters and such that were cartoony at best. Then, after I actually got into fan art of some of the characters I loved throughout cartoons and such, I learned from the actual art styles and creativity of certain artists, and wanted to create my own. I felt like I really wanted to create a character or place that some other young artist would look at and say, 'that looks cool, maybe I should do cool stuff too' Ever since, I have really changed in my views and general ability in my art because, I would have to admit, a bit of envy at how great those artists are and how I want to be great like them.
Devious Comments
I never drew too many pictures of characters from shows or books that I liked but I did try to mimic styles from them. Example: I drew many of my OCs/ fan characters in the style for that world, but I never drew the characters from the original story.