I wouldn't call it typical, but I didn't have any fillings until I was 33. Everyone's biology is a bit different — salivary flow, composition, etc. Probably the most important thing that you mentioned is the limited sugar intake. Carbs => acid => cavities.
Keep in mind that these things tend to deteriorate as we age, so you might not be able to get away with rarely brushing forever.
Keep in mind that these things tend to deteriorate as we age, so you might not be able to get away with rarely brushing forever.