Hi Edward. Ken had a good answer. The only thing I would add to that is that you may want to get several REALTORS to do a CMA for you because they may all be different. Ask the agent to tell you how they arrived at the price.
Here in TN, I look at properties that have sold within a half mile within the last 6 months. Also, I check out what is currently available and what is under contract and how long they have been on the market and how many reductions they have had. All these factors will play a part in what your house is worth. Your house is worth what a ready and willing buyer is going to pay for it--and by checking the last 6 months of sales, pending contracts, and active listings, a local REALTOR will be able to give you a good ball park figure. I hope that helps.