It is between us and the sun, therefore from our viewpoint, the sun only reflects off of sun facing part of the surface. It's the same thing that creates a crescent moon when it's in the same early morning sky.
Venus will be at it's brightest in about a week, then slowly dim as it gets smaller and further away from the sun (again, from our view)
The moon will be right near it (and nearly the same shape) on the morning of Dec 2. On that morning, the moon will be a 13% illuminated crescent, Venus a somewhat thicker 25% lit.
Wayne