Hi,
How are you? Are there other symptoms present? If there is none, there is nothing to be worried about. As Dame mentioned, the head is shaped differently and this can be brought about by how you were delivered when you were born. Take care and best regards.
Everybody's head is shaped differently. However, if it's troubling you, you could make an appointment w/ you GP to get it checked out just to be see if you mom is correct.