Maybe this is something that becomes more important as a person grows older. ...
From what I've read here and on other forums, it seems that by the time high school comes along, everybody wants to fit in and be like everyone else and be popular and accepted. Normal enough of course ... but still.
Yes, that seems mainly true. There is a certain stage before adolescence when people become more concerned with how others perceive them. It can actually be unacceptable to stand out. Girls become interested in their appearance, and can become anxious about it and can see themselves as having body issues. Boys typically become competitive over physical prowess and ability to attract girls. The question of 'normality' is not necessarily about wider society, but conformity with the standards of a small group. At the tough high school I attended, any boy perceived to be weak in any way would be singled out for some merciless mistreatment from the cerebrally challenged bully types that infested the place. There were others among us, myself included, who took a dim view of this and intervened when we could. We were streetwise and physically capable but had brains too, so the bully types avoided us. If they had been honest, they knew they were outmatched and were afraid. Within their own little sub-culture, the bully types seemed to be competing over who had the most criminal convictions and had committed the worst offences. Some had already done time in the 'universities of crime' that were the borstals in those days. To be of a criminal nature was 'normal' to them.
Back to the issue of foreskins and pretending not to have them, the matter of wanting to feel 'normal' in our adolescent years did not extend to comparing penises. Trust me, that behaviour would have been seen as far from normal. It seems peculiarly American.
I read in one of my wife's posts that in her school year, some girls had chosen to start shaving their pubic hair by the time they were around 15, but apparently there was no pressure for everyone to do it. She has said that girls were not comparing each other, so among that group there was no particular pubic hair style that girls had to have to be part of their friendship group and be seen as 'normal'. Similarly, she says they did not compare naked breasts, and I would have been surprised if she had said they did so. Apparently there was some discussion of size but this was always when they were fully clothed.