If you believe in yourself its called confidence. It's confidence if you have something to show for, something that can back up your talk with the actual walk. Lack of knowledge, skill and competence is just all talk, cockiness or even just plain delusional. 

Fearing of what other people might say is just high horse ego, could also be kayabagan in Filipino, that state of mind where you fear that people might say something bad about you, because it will make you reflect that you are not at par with the standards of society or you are lacking something. What people might say about you that are either good or bad. However, it is how you make of things that will truly define who you are as a person and as a professional 

With that said, I am only responsible for the things I utter and not the things you understand because the way people see things are not the way things are, but how the people themselves are. It's all about perspectives.

The question is:  when "change" is constant anyways, Why not change the way you look at things so that the things you see, though the same, will also change?