i mean not to be peesimistic nor optimistic, whichever your prediliction. i too am shy, sometimes painfully so. but i have realised one's life is possibe only one way; to dream of or envy another's life is futile and hollow. despite my failings in front of groups of three or four (from rather gruesome practice this seems my natural limit) i would not shed my innate personality for the confidence of others. to alther one's inner ability (whether public speaking or recognition of one's faults) would be to an attempt to alter one's mind, and to me that would be, much more than mumbling or blushing, the worst crime.
to paraphrase (rather poorly) andre gide: the man whose inner balance is normal can regurgitate; the man who is abnormal refuses the laws of society and can create.
do not, if my advice is worth even a thought, replicate that which surrounds you, follow your innate desires.