Hi, Kim, there have been lots of good answers here. A couple things I would like to add: 1. according to last Sunday's patriot news, homes in the West Shore School District are still selling fairly quickly (average 56 days on market) and 2. in our market, homes are selling for an average of 97% of list price. What both of these things mean to you is that if your home is priced right, it will move fairly quickly, and also that if you are looking to buy in the same area, you may pay close to list price for the home. I personally noticed when I helped buyers find a home in New Cumberland last month that there was a lot less inventory to choose from than in other areas.
Since you are pre-approved for a mortgage, you are obviously serious about making a move. It seems like you are hesitant about hiring an agent, and that's understandable. Probably the first step in your situation would be to invite a Realtor to visit your home to give you a realistic idea for a price and market time for your home, and also to explain the services a buyer's agent can provide. Feel free to ask for references from past clients. If you like the person, get started and let your agent handle all the details for you. A good agent can make the whole situation a lot less stressful for you.
I hope this helps. If I can provide any other information, please don't hesitate to contact me.