And some girls won't know whether it's circumcised or not. Seriously. Dh and I knew so little about circumcision that we didn't know whether HE was circumcised, when we were first learning about circumcision.
Given the rate of circumcision in the USA today - it's quite likely that half of his classmates (or even fewer) will be circumcised. In some areas, the circumcised males will be a definite minority.
On the other hand, as we learned more about how infant circumcision can affect the adult male penis, we realized that some of the intimacy issues we've had are a direct result of dh's infant circumcision. We will be dealing with these challenges for the rest of our married life, and it is lousy on every level.
Continue to research that aspect of circumcision (make sure you're not visiting circ fetishist sites). There is quite a bit of research out there which talks about the negative impacts of circumcision on sex for both the man and his partner. [Caveat: Some men and partners find no problems and no difference - but what if your son and/or his partner(s) are among those who do have problems?]
So maybe the thing to do, is DON'T circumcise - for the sake of your son's future wife. I sure wish someone had talked my MIL out of circumcising my husband, and I know he wishes that too.
ETA: What if you put the $$ you would have spent (or your insurance would have spent) on a circumcision, into a fund -- and when your son is 18, if he wants a circumcision, he can have one on his adult penis,with adequate pain care, and with no worries about fecal matter etc. on his healing penis. I suspect that your son will tell you he'd rather apply the funds to his college education, but you're covered if he wants a circumcision at that point in his life, and it would be HIS decision as an adult.