When I was in high school, I could barely run a mile. I never thought one mile would seem short.
When I started running regularly for exercise, I thought races were for fast people. I never thought I would run one.
When I started running races, I thought 10K was nearly impossible. I said, "I'll never run a marathon."
When I trained for my first marathon, I thought one would be enough. I never thought I would want to do another one (or four).
When I heard about people doing triathlons, I thought it would be fun. But I never thought I could learn to swim.
I have run farther and faster, and swam farther, and biked farther, than I ever thought I could. What are YOU doing that you once thought was impossible?