Children have a very natural approach to nudism, like ducks have to water. Most naturist sites are also welcoming to children. and you will find that children may have a somewhat easier approach to naturism as a first time naturist than the adults.
A personal experience
Last summer my family went to a naturist camping resort, our child was only 3 years old, and I don’t think he could remember being on a naturist resort before. We had been there for three days and was heading for the beach, nude of course – suddenly my son says “They are all nude around here, that’s funny”. He had not noticed that people was nude and had been nude all the time while we were at the naturist resort..