Undergraduate / Success Through Failure - Admissions (conclusion, structure, grammar?) [4]

The following is the text of an admissions essay I am considering using. Any comments, suggestions, and constructive criticism would be greatly appreciated. The essay must be under 500 words.

In particular I am wondering about:
1)My conclusion
2)The structure of the essay
3)Grammatical errors

Thanks for your help.

Success through Failure

The coarse Virginia sandstone felt cool against the palms of my hands as I pressed my body against the sheer rock face. I cautiously located the small pockets and indentations in the rock and gradually ascended the fifteen foot tall boulder. My hands grew slick with perspiration as I gripped the rock tightly, and my forearms began to burn as I neared the top.

My right hand fell against a jagged stone protrusion at the boulder's summit, and I breathed a silent sigh of relief. With the naive confidence of youth, I shifted my weight to my right hand, already anticipating the climb's successful completion. I was rewarded with a sickening moment of weightlessness as the rock protrusion separated from the main rock face, and I unwillingly accompanied the stone fragment to the ground below.

I landed with a jolting thud on the mat I had placed below myself for this very reason. My injuries were negligible; I had managed to escape with only a badly bruised ego. Mother nature: 1, Madison: 0, an invisible scorecard seemed to read. I stared defiantly up at the boulder, challenging Mother Nature to a second round. The boulder glared back, unmoved, uncaring, as the forest seemed to chuckle silently at my failure. My lips formed a smile in anticipation of a second attempt. I have been fortunate enough to experience success throughout most of my life. Yet success without effort is never enjoyable. I live to be challenged, the most memorable victories are never the most easily won. With each failure the prospect of eventual victory seemed increasingly appealing.

With the absence of the crucial rock fragment, the climb's completion became more difficult. I struggled to find an alternative route that would allow success; my first failed attempt was followed by a dozen others as I attacked the climb from different angles. I quickly discovered which handholds offered possibilities and which led to a certain fall. An important lesson accompanied each gut-wrenching drop. Not only does failure sweeten eventual success, it also provides an opportunity for experiential learning. Failure illuminates weakness and reveals mistakes, allowing growth and correction to occur. Even Mother Nature sees wisdom in this timeless teaching style. Lessons taught by failure are quickly learned and seldom forgotten.

Although exhausted and drenched in sweat, I began to piece together the puzzling crux of the climb. Gripping the ledge firmly, I swung my right leg onto the boulder's top. Mustering the last of my energy, I pulled myself slowly onto the boulder's crest much like a young child pulls himself up onto the countertop to reach a cookie jar. I lay there breathing heavily, savoring my accomplishment. Failure taught me how to succeed, and failure allowed me to enjoy my success.