First of all, any answer you get is going to be flawed, because we're talking about growing hair over the course of eight months. There are numbers that work for some people and not for others. Second, if you were really concerned with how long your hair would be next year, why not let it grow until then and cut it to the length you want?

Oh, and I'm glad you clarified the human part. I thought it was time to welcome our new alien overlords.