That is indeed the case, Fla. stat. 743.065(2):
An unwed minor mother may consent to the performance of medical or surgical care or services for her child by a hospital or clinic or by a physician licensed under chapter 458 or chapter 459, and such consent is valid and binding as if she had achieved her majority.
You are forgetting that she carried the pregnancy and birthed the child, which are both… experiences. As I understand it a newborn mother’s brain is rewired during that process, but it’s common knowledge that new mothers tend to be protective of their spawn.
~Max