Too many things can go wrong between the time the lawsuit is served on you and the time all your papers are ready to be filed with the court.

If you are going to do it anyway I suggest you do it while you still have some control over the time it takes to put all your paperwork together and not wait until you have to scramble and risk a creditor seizing assets (wages, bank accounts, etc) as a result of a judgment.

Take a look at the forms that are needed and you'll see what I mean by time consuming:

http://www.uscourts.gov/forms/bankruptcy-forms