I plan on writing a fantasy series at some point. Based on what I've read, my automatic assumption was that the protagonist of such a series would be a teenager, probably around the 17-18 year range. Now I'm not so sure.
Most stories which feature a YA protagonist are to some extent a 'coming of age' story (at least in my experience). I wish to avoid this, as there are other things in my story I would rather address than the generic 'coming of age' themes.
I also want the series to continue for an undetermined number of books (ignore for the moment the logistics of pulling off such a feat). That presents a problem with a YA protagonist, because at some point they stop being YA and become an adult. Unless they are an ageless immortal, which I don't want.
My final reason for considering an adult protagonist is this question which I asked a year ago. The answer to that question theorized that many YA books are 'shallow', mentioning deeper problems but never really addressing them. I definitely plan on addressing some of those 'deeper problems' in my fantasy series, so I'm wondering if an adult protagonist (and by extension an adult audience) would be better.
So it comes down to this: Is there any reason to make a fantasy series YA? Do YAs perhaps read fantasy where adults do not so much?