My personal opinion has long been that I don't have to defend my faith or my beliefs to anyone. They're MY beliefs. I'm not trying to convert anyone or prove that I'm 'right', and I don't need anyone else's validation, permission, or approval to believe the way I do. My beliefs are right for me - they don't have to be right for anyone else.
It can take a while to get to that mindset - there seems to be a deep desire to be accepted (or at least "feel like you're understood"). But ultimately the best "argument" for your beliefs is the in the way you live your life - actions speak louder than words in the long run...