Ok so I am just using the default TwentyEleven theme for now.
I messed around a bit with the css and php files to change it to my needs.
I realized later that I should have made a child theme first- then do those changes.
My question is:
Can I just follow the tutorial for child themes and once that is made (new folder in my ftp uploads) will I be able to just copy the old css and php files that I modified over to the new child theme folder, then do an update without any issues on my theme?