Letting go of 123, and using abc instead

I can honestly say one the most challenging things in this course, was resisting the urge of just writing the numbers on top of the music signs in the book. Having no prior knowledge of music before the course, I did not know how to read music, and found it hard to really remember all the notes. So at the beginning of the textbook, it had the numbers that I could just count off and play, but as i progressed further into the book, I felt like taking my pen and just marking those numbers for safety, in case I forgot. But I think not writing them, help me in biggest way so far.