where should the battery gauge needle be while driving

My gauge only shows 3 positions, low, high and middle. Does not show volts. Holds steady in the middle when driving. IIs this normal?

If it is somewhere in the middle, it should be ok, but the dash gauge is not totally accurate. When your alternator goes out, it will be way down toward the lower end. If you want to check, purchase a fifteen buck multi-meter, set it to DC volts, and connect it between the two poles on the battery when the car is running. If your battery is fully charged, it should read a little over 14 volts.