Trying to center text for plugin authorsure

I downloaded authorsure to hopefully get my authorship on google working. I’m using their footnote and the alignment is off to the left. i’m trying to center the text “By Andrew Schutter on March 16, 2014.” & get it to the size of font I want. I’ve been trying to figure this out for 5 hours. I’m really frustrated. i’m using the twentyfourteen theme.

if you need any of the code, i will provide it for you. someone please help me.