Can I sell my house before my contract goes into effect with the agent?

I signed a contract with a real estate agent last week that will put my house on the market March 8th. I have a potential buyer currently looking at it and is not wanting to wait for that date. Can I get out of this contract without penalty since the house is not technically on the market and the agent hasn't done anything yet? I would like to do this by myself so I don't have to pay out a commission. Does anyone know the legality around this?