Beyond the pontoon

I had spent six Saturdays rowing beside an instructor, and all week I had imagined how satisfying it would be to choose my own pace. Yet, when I reached the empty pontoon, the oars seemed unexpectedly long and the opposite bank much farther away. I tightened my life jacket twice. Then I moved my water bottle towards the bow and back again, although it had been secure the first time. At last, I pushed away. The first stroke carried the boat cleanly forwards. As the voices on the bank faded, the space around me no longer felt empty. It felt as though the whole lake had opened for me.

In your own words, explain the writer's thoughts and feelings before and at the start of making the crossing alone.