If a Scout believes that he has completed all the requirements for a rank, he cannot be denied a Board of Review. BSA is solidly behind this in the new 2011 Guide to Advancement. Section 22.214.171.124, “Boards of Review Must Be Granted When Requirements are Met” clearly spells this out. BSA expects that boards will be scheduled at least monthly, and explicitly says that a unit leader does “not have the authority to expect a boy to request one, or to “defer” him, or ask him to perform beyond the requirements in order to be granted one.”
In other words, you cannot be denied a board of review because a leader says that you are “not mature enough”, you missed an outing or you have not done other tasks that have nothing to do with the specific rank requirements.
So, if you feel that you have met all the requirements for rank advancement, ask for the board. If you are refused, it is time for you or your parents or guardians to speak with the local District Advancement Chair. If you do not know who that is, call your Council and ask!