It's not emancipation that you are looking for. You were an adult at the age of 21 and have been emancipated since then.
That you are your parents' "dependent" is an entirely different thing.
I'm going to take a wild guess here that your dependency has to do with tax returns.
If your parents filed for 2017 and took a deduction for you as a dependent, then it's likely that you are considered a resident of Florida.
A simple fix would be for your parents to file an amended tax return, fed and state (FL), deleting you as a dependent and then you file an amended tax return, fed and state (NY) and take the personal exemption for yourself, making sure to show your NY address on your tax returns.
Your parents, of course, will pay additional tax, but you will get an a refund that you can send to them if you want to.
Both amended sets of returns can be used as documentation that you were a resident of NY in 2017 and other contemporaneous documentation (car registration, mailing address, utility bills, drivers license) should take care of the current year.
Like I said, I'm just guessing.
A lot depends on why you are considered a dependent of your parents and who is saying so.
Clear that up and you may get other helpful comments.

