Hi Sue
How are you enjoying Cairns? Just wanted to say that, like you, I don't like putting my head under the water, but, with the excellent instruction and advice from our guide on our trip to the reef I gave it a try. First time for me (four years ago) and I wished that I had tried it before. I felt quite safe even going "over the shelf", although a yard or two was enough to remind me that the sea bed was a long way down! Around the corals it was quite beautiful. We saw some beautiful fish, sea anemones and so on.
Continue to enjoy your adventure.