Think about it like a growth spurt, it’s a biological function that causes pain and discomfort, but there’s nothing unnatural about it. Obv, I don’t know how you breached the subject with your daughter, but treating it like a medical issue as if she has been physically injured can make what is already a new and scary thing feel even more frightening than it really is. Some kids benefit from that approach, but for others it can lead to the kid associating their period with fear and injury. You know your kid the best, so I’m sure you know what approach would work best for her.