Very good.
Well, lets look at it this way: You're sixteen. This looks better than a lot of the adult-made content on this site. This is proof that you could definitely go places in the future. I'm sixteen; you're obviously lightyears ahead of me. I have a lot of respect for that, to be honest.
Now, onto the piece itself. I've never been much a fan for gross art, but this does pull it off masterfully without coming across as overly disgusting and distasteful. There's lots of detail here in her wrinkles and folds. The color scheme works nicely and the subject really captures the viewer, for better or for worse. My only qualm with this piece, however, lies in the hair. Her hair is just a shape with some folds, and doesn't look like a part of her head, almost as if it's a turban. Hair is far more fluid and organic than that. This is especially true with her ponytail.
Overall, amazing work. You have massive amounts of potential.