Your efficiency at moving through the air is a combination of your bike position, clothing and equipment. For example as soon as you put on a rain jacket your CdA will increase and you will go slower for the power.

Your CdA should be viewed in context, a road bike position is less efficient than a time trial position. Wearing an aero helmet is more efficient than a standard road helmet.

Time trialists can aim to have a CdA below 0.2, however this is by no means the average which is closer to 0.22-0.23. A road bike racer can be as low as 0.24 but the average is closer to 0.27. A regular road bike and standard helmet in the summer is likely to be 0.3-0.32 however in the winter this can be much higher.

A performance cyclist should pay continuous attention to their aerodynamic efficiency. So whatever your current CdA you should attempt to lower it. It is in most cases more important than losing weight, although losing weight is also a good way to reduce your drag.  That said, a beer belly is apparently more aerodynamic than a flat stomach!