The hair is interesting, colors are nice... However, I feel the profiles proportions any facial features are a bit off. Here are some things I noticed...

- The cranium is a bit on the small side. The frontal width of the head looks alright, but the cranium should extend farther back at this angle. About 7-8 pixels past the ear.
- The facial/neck wrinkles are not very realistic. I suggest spending some time studying pictures of elderly people and how and where the wrinkles are formed.
- The placement of the ear is not correct. It should be higher. A general guideline is the top part of the ear (where it connects to the head) should be aligned horizontally  with the eyes. The bottom part of the ear (that connects to the head) should be aligned horizontally with the bottom of the nose.

I hope I was helpful! :D Keep up the good work!