Born circumcised

My age is 27 years and I am not married. When I was born I was not circumcised. Recently when I went to the doctor for circumcision, the doctor told me that I do not need circumcision as there is no foreskin over the head of my private part. In medical terms this condition is called aposthia, which is rare, in this case there is no foreskin naturally to be removed. When my private part is flaccid, the skin doesn't cover my private part head and also doesn't cover when its erect. But there is very little foreskin which, when I pull then when my private part is flaccid it retracts back. My private part looks like it is naturally circumcised but in actual fact its not. I am curious to know whether I still need a surgery to remove more skin or its just fine and I do not need to undergo a surgery. Will I commit a sin if I do not undergo circumcision? What does Islam say about natural circumcision?