In Florida, the age of consent is 18, except that 16 and 17 year-olds can consent to sex with someone 16-23. This girl is definitely below the age of consent. A complicating factor that none of the reports mention is that some of the boys may also be below the age of consent.
It's a truly horrible thing and I am glad that law enforcement is investigating further. Also the references about the girl and her mother not wanting to press charges concern me. I understand that, but in Florida, as in most jurisdictions in the US, it's the state's decision to pursue charges, not the victim's. Granted, a victim's reluctance makes it difficult for the state to go forward, especially because you would not want to compel a victim to testify under penalty of contempt, but with compassionate support by victim advocates, many reluctant victims find the courage to go forward.