Well if you're talking about peak fertility, which is not being "fully mature", then according to the American Society for Reproductive Medicine, that is in a woman's 20s, not any of her teenage years. https://www.reproductivefacts.org/n...t-sheets-and-info-booklets/age-and-fertility/ You do not give any benchmarks for your other observations besides "fully mature" and "fully developed". If you take both of these in broad senses then both are incorrect; women continue to develop mentally and physically their entire lives. Maturity can be measured in many ways, among which brain maturity, hip/breast size, and even basic measurements such as height are not nearly finished by age 19. So again, I am asking you to clarify what you mean. I see on your other posts that you are in fact a physician and you performed an abortion on a family member (of course either through surgery or medication I'm sure), so you must have some very good resources for us to check out!