Today I flew in a tiny propeller plane high over and through the mountains of southern New Zealand. I was terrified until we were in the air and then I relaxed and enjoyed the view.
Your characters also need to try new things. With your character in mind, make a list of things she might be afraid to do. Think extreme, such as jumping off a bridge or letting a tarantula walk on her arm.
Next imagine how he would behave just imagining the experience. Think fear, terror, panic, anxiety.
Write the scene using descriptions that let the reader be with your character.
Have fun with this one.