The problem with this question in martial arts, but also in other areas of life, is that most of the time you’re not. Time and time again, you tell yourself that you need a little more time to be ready. Is that really the case?
Or do you just try to stay longer in your comfort zone until you feel “ready”? Another question: when is one ready? As students, can we really gauge that?
During my little 15 years in Bujinkan, I could never choose the timing of my graduation. Each time I was surprised anew and did my best to cope with the situation (Banpen Fugyo 万変不驚).
For me, each graduation I have received is a huge responsibility and a leap of faith from those people who have walked the path before and whom I trust myself. With Each new rank I was thrown out of my own comfort zone, however, at the same time it also helped me to push personal boundaries and thereby expand my mental also as physical capacities (Saino Shin Ki 才能心器).
This little “push” into the unknown has always opened up new paths that were previously hidden from me (School of Hidden Doors). At the beginning of my Budō, these graduations had a great importance (for me personally), which, however, became less and less with increasing years of training and are now only numbers. However, what is left behind are the lessons and beautiful moments that came out of each one.
Please do your best on your Budō and try not to overthink simple things. This may cause your inner hidden doors to never open. Trust your teachers, because only with trust is heart-to-heart transmission possible (Shinden 心伝).
The quintessence lies in the heart
極意は心に有る
Takamatsu Toshitsugu
Happy Training! 
Little side story:
During one of my training trips to Japan and after a training session with Nagato-Sensei, he wanted to graduate me and I, in my youthful naivety and without thinking about what message I was sending, declined. I was later pointed out by several people that I was indirectly saying that I had a better understanding of the subject than he did. He later approached me and said it again, the difference being that this time I accepted with thanks. This time he added: “Don’t take if for yourself, take it for your country”.