There are three types of confidence:

a. Delusional confidence - unsupported and unearned belief that you are completely capable of what you set out to do.

b. Confidence through necessity - acting with confidence due to a situation requiring it. You don't feel confident internally but you act confidence as you realize it is a necessity for success.

c. Acquired confidence - genuine confidence found through trials and tribulations. The best form, but also the hardest to obtain.

While on the surface, some of the types of confidence are better than others, in most cases all that matters is that you are confident. There are so many successful dumb people that were able to succeed through delusional confidence. Sometimes all it takes is truly believing you can accomplish what you set out to do.