In the example above, the writer uses the word "I" seven times in three sentences. Of course nothing is wrong with the word "I" -- you will and should use it in your essay -- but you want to avoid overusing it.
The example above can be rewritten so that instead of seven uses of "I" we have one: "Soccer has been a part of my life for longer than I can remember. Literally. My parents have photos of me crawling around as a baby pushing a ball with my head. My later childhood was all about soccer -- the community league at age four, and participation in regional tournaments by ten."
Don't worry too much about frequent use of "I" unless your essay starts to sound like a broken record. When you use the word multiple times in a single sentence, it's time to rework the sentence.