There seems to be some disagreement on the ages at which female chimpanzees typically reach sexual maturity and when they typically first give birth, but regardless, different sources seem to agree that a number of years elapse between these two milestones.
For example, this 2018 paper from Jane Goodall and colleagues found
… an average age of 11.5 years (range 8.5–13.9) at sexual maturity and 14.9 years (range 11.1–22.1) at first birth. These values exceed previously published averages for wild chimpanzees by one or more years. Even in this larger sample, age at first birth is likely underestimated due to the disproportionate number of non-dispersing females, which, on average, give birth two years earlier than dispersing females.
In humans, there is also a substantial lag between these two events, but we understand this as a very common cultural dividing point, which places the first firmly in childhood, and the second (generally/ideally) in adulthood. The maintenance of this interval is controlled by a variety of social and societal practices and institutions, across cultures.
Do we know what maintains the lag between the biological capability for reproduction and the actual first birth in chimpanzees? Presumably there is also some sort of set of social practices among chimpanzee society that maintains this. Do we know to what extent it is controlled by mature matriarchs or patriarchs, or by actions taken by the young females themselves, or some other set of behaviours?