I’m not sure anyone is saying she was under legal age.
They are claiming she was 17, and she posed as 18 on that website. And there is no evidence beyond the statement of another whore that they were ever together.
The FBI (Big fans of Gaetz) looked at it hard. Finally someone wore a wire and they caught them discussing the scam.
Even F-Troop didn’t try to press charges... against Gaetz, who they dislike.