I decided to learn http://www.cs.cmu.edu/~15455/ first, before progressing to the graduate course by Ryan O’Donnell.
As I have learned most of the material before, I have plenty reason to believe that I will finish with 15455 soon.
Yet today I found the course to be more difficult than I imagined while doing the first assignment. The course by K. Sutner offers more material than the textbook offers and the course can probably provide me a deeper understanding of the material, so I decided to put effort in it to finish it soon.
I promise myself to never see the solution while attempting the homework. Only when I give up will I see the solution.
Today I learned the first two lectures and finished the first Assignment. I expect to learn more efficiently in the following days.