I think my grandson 5 1/2 will have no problems
he already told the neighbor boy that his penis is so short because his parents circumcised him and his is long because he is intact (and he was proud of it).
We had 4 boys from Berlin, Germany over here for a few weeks and they all changed swimming trunks right in front of him and of course all of them were intact. One day my grandson decided to tell them that they are lucky that they were not circumcised. :LOL
The funny thing was that they were 8 - 15 yrs. old and had no clue as to what he was talking about, since they had never seen or heard anything about circumcision.