I believe that this goes to show that anyone can fill in the dark figure representing the athlete. Thus anyone should be able to consider themselves as an athlete. It's not a word reserved for those who receive a paycheck from participation in a sport.
The word athlete is controversial and loaded with stereotypes as previously discussed. You can find the word defined in many drastically different ways. Merriam-Webster's dictionary defines an athlete as a person who is trained or skilled in exercises, sports, or games requiring physical strength, agility, or stamina. On the other extreme end of definitions, the Nike mission statement quotes the legendary University of Oregon track and field coach and Nike co-founder Bill Bowerman stating, “If you have a body, you are an athlete.” This just goes to show that whether you're the fastest individual or the last one across the finish line you can be called an athlete.
Instead of searching for the perfect definition to follow in order to be an athlete, I encourage you to think about the commitments you set forth. Think about the time you've spent working toward a goal and your perspective towards being an athlete might change. From a psychological standpoint, believing that you're an athlete can have such a positive impact on your performance. As your performance improves, the way you perceive yourself improves. Believing and perceiving are two major things that lead to achieving. A sense of achievement is another telltale sign that you're an athlete. At the core of every athlete there's a great sense of accomplishment that comes from earning a medal, or simply being able to say "yep, I did that."
In the end, if you have the guts to show up and to complete a goal, then you're an athlete. I wouldn't let anyone tell you differently.