Took me 5 years to achieve my dan grade, but I missed quite a few classes for a while for various reasons. So I was a black belt by the time I was 13 and teaching adults and large classes in general which was very daunting at first but in time it got easier. Then when I became 16 (or just before I was 16, cant quite remember) I had to drop down a grade for a bit, and go through knife and stick defences, leg sweeps, imobilising holds and bone dislocations to earn my senior dan grade. For the next 7 years I stayed a 1st dan, purely for the reason I had no interest in grading anymore. Then I was told I was grading (even though I didnt want to), and I achieved my 2nd dan, and it was because of that grading that I really got into bunkai and learning about other arts, and I know so much more because of it, so I'm glad they made me do it