You can be shy and brave. Shy is how you feel. Brave is what you do.

Shyness is a temperament and bravery is a record of things you did, so they are not even the same kind of thing. People treat the first as a disqualification from the second, which collapses a feeling into a behaviour and leaves a lot of quiet people convinced the category is closed to them. Doing the hard thing while shy is still doing the hard thing, and the internal weather does not get subtracted afterwards.

Stop waiting to become outgoing before you act. Pick the action, keep the temperament, and let the discomfort come along without giving it a vote.