Why Does Age at First Reproduction Matter in Population Growth

Why does age at first reproduction matter in population growth?

A) It doesn't really. As long as women are reproducing there will likely be population growth.
B) Babies are less likely to survive if mother are very young.
C) Very young age at first reproduction indicates some level of hormone-mimicking pollutant, which will eventually result in a declining population.
D) If a woman starts having children at a younger age, she is more likely to die, reducing population growth.
E) If a woman starts having children at a younger age, she will have time to have more children, increasing the population growth rate.