You can file a charge of discrimination either on the state level or on the federal level. In most cases, filing such a charge with either will result in it being dual-filed with the other.
Under the federal Age Discrimination in Employment Act, which protects persons who are at least 40 years of age, a charge must be filed prior to commencing a lawsuit. A lawsuit can be filed so long as at least 60 days has passed since the charge was filed, so long as it is not more than 90 days after notification that the Equal Employment Opportunity Commission's investigation has concluded. The federal law applies to employers who have at least 20 employees.
To file a charge of discrimination with EEOC, there is a 180-day filing deadline, which is extended to 300 days if there is a state law that prohibits age discrimination in employment and a state agency that enforces that law.
My understanding is that the Florida Civil Human Rights Act also makes it illegal for an employer to discriminate on the basis of age, and that a claim of discrimination can be filed with the Florida Commission on Human Relations. Florida's statute covers employers who have at least 15 employees and requires filing within 365 days of the date of discrimination. Nonetheless, it is better if you file as promptly as possible.
Please note that I am a New York attorney and thus cannot advise you as to the application of another state's substantive or procedural law.
Good luck to you.