Legal Question in Family Law in Florida

You are way too late.

If there has never been an order for child support, then your time to collect has passed. If there has been an order out for child support since before your son turned 18, there is technically no time limit to collect. There is, however, in Florida, a law called laches (pronounced like "latches"), which says you just can't do nothing then expect to one day go after the money. If you've tried to find him and he's been difficult to find or he's hidden (you've called, checked the internet, checked hospitals and jails, checked with his last known employer, etc.), then you may still have a chance to collect. If you've done nothing for two years or more, your chances of collecting are probably lost.