The unknown is not automatically dangerous; it is simply undocumented.

Unknown and dangerous get filed in the same drawer, and they are not the same thing. Most of what you have not experienced is simply unrecorded: you have no data, so your mind supplies the worst available scenario as a placeholder and then treats the placeholder as information.

When something unfamiliar frightens you, separate what you actually know to be risky from what is merely undocumented. Then go and document some of it: talk to someone who has done it, try a small version, read an honest account. Converting unknown into known usually removes most of the fear without requiring any bravery at all.