So if the moon was ejected from the earth, why is it so round. Wouldn't it be chunky or odd shaped like an asteroid?
Lots of gravity and lots of time.
Most of it was molten or in tiny pieces. Gravity then would draw it all into a spherical shape.
The Moon's shape is a function of its mass.
If you look around the universe you will see various examples of rotating bodies. They are all aggregations of matter. They are in pretty well defined structures. Consider the rings of Saturn. As they aggregate and take on more mass they will become spherical and the unequal distribution causes wobbling that eventually stabaiizes as rotation.
The moon was once a ring of particulates flung out by the collision. Time and gravity collected the particles.
The moon has five masscons, that is five regions of excess gravity where the density of the material is higher than the rest. That is about as lumpy as it can be since its gravity will otherwise make the body spheroidal. The earth also has masscons and is nearly spheroidal.