If I’m being sued for an accident involving my car and a child what are my options?

A threat to sue and an actual lawsuit are two different things.  You don't need to go into full stress mode until you receive a demand letter from an attorney or you are served with official court papers which advise you that you have 21 days to file an answer.  Based on your question, it sounds like mom is trying to bluff some money out of you... so you don't really need to hire an attorney right now.  However, you should still be somewhat proactive and be prepared for the possibility of a suit.  Things you can do include getting copies of statements from anyone who saw the accident, get copies of any accident reports, and gather your insurance information that was in effect at that time.  Also get any info about how the child is doing now... since this may be a mitigation of damages case.  If and when you do receive notice of a lawsuit then contact the insurance company that you had in effect at the time and get them involved.  They should provide you with some representation.  If you did not have insurance, then do what you can to set up a payment plan with a personal injury/defense attorney.  Regardless of who you contact, make sure that you file a response to the lawsuit.  It this incident is as old as you describe, mom is going to have some issues because of how long it's been.  If you fail to answer, you are waiving your defenses and subjecting yourself to the possibility of a default judgment.