After reading other practitioners' experiences in memorizing the Fa, I also want share my own experience. I too am currently memorizing Zhuan Falun, but not as quickly as other practitioners. I only memorize one page per day and am memorizing paragraph-by-paragraph.
I remember that when I was in school I was most afraid of memorizing things. Often I could not memorize one small paragraph after several hours. I failed to pass almost all the classes related to memorization. After obtaining the Fa, one day I was taking an exam arranged by my workplace. I was able to answer more than 500 questions in a few days. I know that this was due to the wisdom brought by Falun Dafa. I also know this wisdom given to me is not to accomplish things in ordinary people's daily life. I must memorize the Fa. Although I don't have much time, I memorize one page per day. Within one year I should be able to recite all of Zhuan Falun from memory.
Slow progress is not the primary issue, but making no effort at all is the issue. As long as I am persistent, I should be able to memorize the Fa. I have a sister who has not yet started practicing Falun Gong. She only reads Zhuan Falun when she has the time. She has already felt the wisdom brought to her by Dafa. She is over 40 years old, but her memory is much better than before she found Dafa. Practitioners should not worry about their ability to memorize the Fa. Fellow practitioners, the earlier you start, the earlier you will be able to finish memorizing the Fa. This is just my own understanding. Please point out anything improper.