Centering isn't working in my document(title and name)

[Meenie50]

I'm an author. In my document, when I enter the title and my name it should be centered but it's not. I can see that it's slightly off. Why?
I'm talking about at the top of the document
Title of Book
by
My Name
It's off by several letters of being centered.
I use the default page setup, hit "center" for the alignment, then type in the info, but it's off.
Any ideas? Thanks!