A Florida high school teacher has been charged with having sex with a 17-year-old student multiple times on campus. Heather Mashburn-Smith, 37, was arrested on Wednesday after police received a tip-off that the teacher had had sex with a teenager twice in the past month, the  Charlotte County Sheriff’s Office said in a statement . She then gave a “full, post-Miranda confession” to detectives and was charged with unlawful activity with minors, enhanced to a first-degree felony because she’s a teacher, police said. The age of consent in Florida is 18. Florida high school teacher Heather Mashburn-Smith allegedly had sex with a student twice on campus. Charlotte County Sheriff's Office “What this woman has done is not just unlawful, it is damaging to the students and staff around her,” Charlotte County Sheriff Bill Prummell said of the teacher who was also suspended from her job at Port Charlotte High School.…