Editors' note: Denise Castelli is one of seven CNN viewers training to race the Nautica Malibu Triathlon with Dr. Sanjay Gupta. In 2009, Castelli had her right leg amputated below the knee after contracting an infection.

Malibu is just more than a month away, and I’m closer to the finish line than ever.

What I’ve realized is that this whole adventure is not about the finish line. For me, it’s about the journey and, let me tell you, I’ve grown exponentially in the past seven months. It's all because of triathlon.

When I began, I naively assumed what most people would about this challenge. I would lose weight, get fit, cross that finish line, and then obtain my new bragging rights as a triathlete. What I didn’t know is that along the way I’d discover who I was as a person.
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Denise Castelli is one of seven CNN viewers participating in the Fit Nation Triathlon Challenge. When she's not swimming, biking or running, she's using her newfound to confidence to motivate others to change their lives.

We’ve all had that horrible dream, right? The one where you have a microphone in your hand and you’re standing on a stage in front of hundreds of people only to look down and find that, to your horror, you’re standing in nothing but your underwear.

Well, in my dreams when I look down, I happen to see only one leg.

Truth be told, I do only have one leg.  I also often find myself standing on stage holding a microphone in front of 200-plus people.  During these moments, right before I speak my opening line, as I can feel everyone's eyes on me, I almost always glance down for a second and think, "So this is your life now?"
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Editor's note: Denise Castelli is one of seven CNN readers chosen to be a part of the CNN Fit Nation Triathlon Challenge. She lost her leg to an infection following a tragic accident in a collegiate softball game.

My entire life I've been blessed with two selfless parents who have given me everything.

I was fortunate enough to be afforded many opportunities. I played the piano and clarinet, took art classes, played softball, bowled... the list goes on. We had a home cooked family dinner every single night and always found ways to spend time with our entire extended family.

My parents gave me vision to see the future, strength to face the many battles of my life and unconditional love that made me unafraid of failure.

I always know, no matter what, at the end of the day, I am still loved and they are always proud of me. When you really think about it, that's an extremely powerful thing.
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Editor's Note: Denise Castelli is one of seven CNN viewers selected to be a part of the Fit Nation Triathlon Challenge program. Denise lost her leg to an infection following a tragic accident in a collegiate softball game. Last week, she received words of encouragement from two-time Olympic softball player Jennie Finch. Check back on CNN.com/health for more on Finch later this week.

For as long as I can remember I’ve been a ball player. In fact, softball has been the only constant through out my life. But for me, it has always represented more than just a game. It was an opportunity - a chance to push myself, to achieve goals and build strong relationships.

While those relationships were often with teammates, it also (if not more importantly) solidified my bond with my father. We spent numerous evenings on the field, practicing fly balls over and over. Ball after ball, he would keep hitting to me until the sun went down.

It was during those summer evenings that my passion for softball was ignited. From that point on it was the only thing I ever wanted to do.
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Denise Castelli is one of seven people chosen to be a part of Dr. Sanjay Gupta's Fit Nation Triathlon Challenge. As a recent amputee, Denise is searching for a way to reclaim the feeling of being a competitive athlete that she cherished before her accident.

Getting in the pool has forced me to face a number of fears. The first being the obvious fear - ditching the doggie paddle and actually learning how to swim. The other fear is not so obvious and much more personal.

The swim is the only leg of the race that I’ll be doing, well, legless. Prosthetics aren’t made to be submerged in water and I can imagine it would be quite difficult to swim with a heavy piece of carbon fiber attached to my body.

My prosthetic has been my safety net ever since I learned to walk again. It has essentially become my super hero cape. When I wear it, I know I can do anything. I have the world in the palm of my hand. Without it, am I handicapped?
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