That's really your call. You have no other debt and there is no word from anyone that this debt has been sold or a judgment has been obtained?
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here. Please visit my web site: www.avanesianlaw.com for more information about my services.
If these are you only debts and you have not received communication from a California attorney regarding the debt then I would wait to see if the statute of limitations expires. There are a number of things which can toll the statute of limitations and give the creditor more time to file suit but none of these are raised by your question.
Unpaid medical bills are not as bad for your credit as a bankruptcy. Although the SOL may expire after 4 years, the accounts may stay on your credit or 7 years. A BK will stay on your credit for 10 years, and it will affect your relations with your other creditors.
Also, the SOL may not necessarily be 4 years. Sometimes a shorter period applies. To get more specific advise, relevant to your exact situation, you should sit down with a lawyer.
The SOL generally starts on the date you are declared in default on your obligations. In this case, 4 years unless the contract states otherwise.