I'm working on exercises in a book, and I'm kinda stuck.

These are the steps

draw button with ellipse tool
switch foreground/background (white/black)
select Type tool
click on ellipse shape
type "button" (which creates a new layer)
enter settings in Type Pallete ie; pixels, font, center button.

Well it's not really centered. What can I do?

The exersize goes on to add bevels and shadows and stuff.