The statute of limitations is an affirmative defense, and usually needs to be plead in your first responsive pleading. That would then normally be accompanied or followed with a motion to dismiss for failing to state a claim upon which relief can be granted. Failure to follow the court rules could result in a loss of the defense. You really need an attorney to assist you in the defense of this claim so it gets done right.
I agree with my colleagues on this question. You stand a very good chance of fending off a judgment given the facts above. However, to do so requires that you timely file a response to the lawsuit, and that your defense contains a reference to the expiration of the Statute of Limitations. They will take advantage of you if they can. Please get in touch with local counsel to advise you and assist you with your defense. Good Luck!
In addition to having a general denial in your answer, you would include a section called "affirmative defenses" and list limitations as an affirmative defense.
I hope this information answers your question. If you need more information, simply add a comment or call me. Good luck!
You may have a valid limitations defense. You may have other defenses available, too, depending on facts not stated in your post. However, no defense is worth anything if you don't know how properly to both plead and prove it. Therefore, I agree with all of my colleagues that you need to hire a lawyer to defend you. I'm sure your adversary has a lawyer. This puts you at an enormous disadvantage unless you have one, too. Representing yourself would be like trying to drive a car with a blindfold on.