One of the reasons you should consistently show your baby that your activities are fun is that she is learning what is fun, scary, happy, or sad from you. And this holds true for all experiences such as being in the dark. Be sure to allow your baby to positively experience a dark or dimly lit room. This can be done with the shadow activity (see Infant Stimulation Activity 63) or any activity that can be just as fun in the dark.
For example, start doing something simple like rolling a ball in a lit room, then turn off the lights and continue the activity in the dark. The contrast of playing in the light then the dark will be very interesting to baby. It may also save you some strong emotions if you are ever in a power outage or someplace where the lights need to be off.
You can also play while using a flashlight to get your baby accustomed to what that looks and feels like. Again, this is not only interesting to baby, it paves the way in case you are in a situation where the flashlight is your only light source.