Do not agree to let one agent represent your home for more than 90 days. It seems to make most agents work a little harder knowing that their time is limited. Not said to knock agents, it is just human nature. Firm deadlines often create more productivity.
I know the market has changed, but here is how I sold five houses over the years, all in less than 30 days. One in just two days and the last one in just eight!
Spend the money, and get two independent, professional appraisals. That is what your property is really worth and is the maximum most lenders will approve. Set the selling price at that price and work from there. This is the accurate value, not what a realtor or someone else thinks they can sell it for.