3 weeks may be too early to tell but it depends. Has there been any interest? Any viewings with feedback? Did you set the price at the upper end of expectations?
Depends on the property movement in the area and the type of property. Have a flick through Rightmove for similar properties in your area. Beware that some agents will advise you to lower your price too soon so they can make a quick profit. Three weeks would be far too soon where I live. This time of year isn't the best time to get a quick sale.
It also depends on how quickly you want to leave. Do you have anything else lined up to buy? If you are prepared to wait, hang on and you may get someone who wants it desperately- eg to move near to family or a school, and will pay the asking price.
Things won't pick up now until the beginning of march on the property front. Don't be too hasty to drop the price -most potential buyers offer at least 10% less than asking price for their initial offer . A drop in asking price hints at desperation - hold on for a few months yet. ( I'm a retired estate agent/property valuer)
It seems too soon...both to reduce the price and early in the year to have it on the market. Too soon after Christmas. I seem to remember hearing that early spring...March and April...was the best time.