You're both in it for the challenge, so its not like either of you is going to steal ideas or whatever from the other.
posting and seeing wips might even motivate you more.
All my heads look real bad till they are about 75%done. Just power through, and as long as you are willing to erase parts to make it better your fine. On mine I think my sketch looked nothing like the final, but it's easier to work with something on the canvas in my experience.