a dip/ indentation/ baldspot on my head

Im 22 and was told that I was born with the 2 or 3 small indentations on my head.
The indentations are clustered together, and no hair grows from it (which makes it very difficult for a girl with long hair to keep my hair down =( ).
Its neither sensitive nor swollen.
I was told by my parents not to worry about it, and that I was born with it, but it still seems very unusual.
Is this something I should worry about?