My hernia is about the size of my fist. Is that larger than normal?

Yes. The size of a hernia varies by the location of the hernia (groin, belly button, etc) and the size of the patient. However, regardless of these variables, a fist-sized hernia is large and should be repaired sooner rather than later.
What's normal? Hernias of any size are not normal, and the size can refer to the hole in the abdominal wall, or the lump under the skin that represents the abdominal contents protruding through the hole. In general, larger lumps and holes are more difficult to repair than smaller ones, so you should at lease see a general surgeon for a consultation to get more info about your unique case.