The Quresh, and following them most Arabs, even during JAHILIYYAH used to circumcise their boys at age 7-8 years. It was so because the people in the Arabian peninsula considered themselves as descendants of Prophet Ibrahim.
Some historians have written that the exalted Prophet was born circumcised. However, Allama Aslam Jairajpuri of Delhi writes in his TAREEKH E ISLAM that the circumcision was done on the 8th day of his birth.
The so-called Imams adopted another Jaahiliyyah custom/ritual from Biblical blood sacrifice and Islamized it through fabricated Hadith as Aqeeqah.
To this day N2I Muslims believe in blood sacrifice on the 7th day of the birth of a child. The fabricated Hadith kept alive by tradition commands them to sacrifice one goat if a daughter is born and two goats if a son is born. [Notice the discrimination right in the beginning?]
Then the baby’s head must be shaved on the seventh day and silver of equal weight distributed among the poor as Sadaqah (charity). Imagine the weight of silver making mockery of Sadaqah. The male child must be circumcised on the eighth day.
Here is the height of calumny, “He heard from him who heard from that who heard from … and so on: Abu Huraira narrated from Rasoolullah that a child’s soul is held as collateral (Raheen) by Allah until his Aqeeqah is done. Or, the Rasool said something like that.” [Qanoon Al-Akhbaril