Does it really matter? Let s/he be. Just because s/he doesn't share your (okay, our) musical tastes, no need to run a potential jazz fan off.
this person is here to distract us for personal gratification. say g'nite gracie. potential, my ass.
Very well could be.
Simply put, there are two options. One, Danielle is exactly what she says she is: a 14-year old girl interested in jazz. And here we go - yet again - running a potential young jazz fan out of our "clubhouse."
Conversely, she could be some old dude wasting his time and ours by posting on some jazz forum that s/he really cares nothing about. If you believe that, just ignore him/her.
Frankly, I'd rather err on the side of having a few minutes of my time (humorously) wasted than gang up and chase someone off. It's the internet; I've been fooled before and I almost certainly will be again. It's no big deal...