This debt was made in Florida but they are trying to sue me in Washington State. It's almost 10 years old, can they really sue me for what I owe
There is no trying to sue. There is only sue or not sue. If you haven't been served a summons and complaint please be more clear about what is happening to you.
If you have been served then you know that they CAN sue you because they DID sue you and now you get to raise the statute of limitations as an affirmative defense.
The SOL in WA is 6 years for written and oral contracts. In FL it is 5 years for written and 4 years for oral. Unfortunately, FL's SOL was tolled (stopped running) when you left FL per 95.051(1)(b) so that gives the creditor extra time to sue.
A WA court might allow that extra time under its Uniform Conflict of Laws - Limitations Act. Or it might not. If you actually have been served a summons and complaint we can go into that further.