You might be worried about having “that talk” with your daughter about puberty. You will probably also be embarrassed discussing body functions and don’t know the right words to use.
Most parents don’t want to bring up the subjects of sexuality and reproduction to their ten year old daughters. That would mean accepting your little princess is growing up and the thought of her understanding sex education is a discovery you would rather put off to much later! The problem is that hormonal changes begin around 10 years old so it is better to support her so she is prepared and understands what is happening to her body.
You might imagine that there is a fixed age to discuss puberty with your daughter but like most of the things you have already taught her, it is much easier and more effective to introduce the changes in her body and how she is going to feel as she grows and develops.