You say what you are trying to predict is a continuous variable, so why would your output by discrete? It seems your predictors (inputs) are discrete based on what you said.
Anyhow, the size of the Mean squared error is really going to depend on the units in which a quantity is measured. That is if my response variable is measured in nanometers my MSE will be much larger than if measured in kilometers. Alone it means little, but can be useful as a comparison.
