I am a relatively fast pattern learner. I am 17 and a 3rd dan and I learned Yoo Sin (the second longest ITF pattern) in one night. And it is to the level where I would be comfortable competing with it even only a day of having it. One I have a great memory. But, two; I also have been training for over a decade and as you get better and progress patters come easier and easier, pus the fact that I'm 17 and still young.