Book about the Sister of Moses?

I remember reading a book at least a few years back that was about the sister of Moses, but a fictional one rather than Miriam. I believe the sister's name was Alma or Almah, and she was a dancing girl and eventually became an Egyptian priestess.

I think it was a book for young adults, and am almost positive that the author was a man.

Anyway, I can't remember the name of it for the life of me, and so I thought I'd ask here. Thanks!