You can do it at any time and on any date. An imporant rule is to never begin Magick/meditations during a Void Course of the Moon, because it will fail (Moon VoCs can be a good thing in certain ways - things begun during one don't last), but Satan is more powerful than them, so He knows that you're dedicating/have dedicated. Of course, do it when and where you will not be interrupted, and can concentrate and do it properly. If you don't have all of the tools as described, then that is not too big a problem. The important part is the actual meaning of it, taking it seriously and being sincere and genuine, and having the blood on the paper.
Good luck!
