Head circumference too big?!

I'm so scared that my baby's head grows too fast. At one month his HC was 37cm. It grows pretty fast like nearly 1cm per week. Doc doesn't look concerned about it, but he said we can take MRI if I'm worried. And every people who comes to visit says that his head is big. I'm so afraid that something might be wrong. Hopefully not. Just praying to God that he is a healthy baby.