Some commercial operations wait until the hen is about 22 weeks old before they incubate the eggs. I say some because I don't know what they all do. A reason for this is that the small pullet eggs don't have enough nutrients for the chicks inside to develop really well. The chicks that do hatch will not be as big and strong as chicks from eggs that have more nutrients inside for the chick to use to grow. The hatch rate is not always as good as with older eggs either.
I am not saying that the little bitty pullet eggs won't hatch. Many of them will, often as many as from larger eggs. I am not saying that these small chicks will not survive and grow. Many of then will. I don't know if those little chicks will grow as much as the ones hatched from larger eggs. The genetics are the same, so they might. I'm saying that those that do hatch start out behind and the commercial operations feed the chickens a while longer before they start incubating eggs.
What you decide to do will depend on your goals. Good luck!