If you are 18 and she is 16, then per FL law sexual activity is legal. Subsections 8a and 8b of 794.011 apply to those in a familial or custodial relationship. As long one is under 24, a relationship with one 16 and up is ok.
Mr. Grieco is correct. Here is what you need to know:
A person under 16 cannot legally consent to sex with anyone.
A person who is 16 or 17 can legally consent to sex with someone who is 16-23.
A person who is 18-23 can legally have sex with anyone 16 or older.
A person 24 or older can legally have sex with anyone 18 or older.