I worked soooo hard on this short passage!

There are times when writing is easy and fun, but there are times when I can work for hours to get one sentence just right. I like this passage a lot, but it was hard work. Now I look at it, and I see a grammar error! Can you find it? Even so ... ain't this pretty?

I leaned back and stared out at the stars, my thoughts drifting. I had no religion, unlike Zoey and Carson. Everything was a mystery to me.

I remembered my mother and me on vacation in California, one of the last natural places left in the world. My favorite place had been Yosemite National Park, a land with such a profusion of beauty — there were rock formations glowing at night, waterfalls as big as mountains, trees so tall they blocked the sun and formed cathedrals of lush darkness. While there I was overwhelmed by sudden spiritual feelings: the world and its mighty bigness, me and my mighty smallness, the mystery, the infinity, the unanswerable riddle. Compared to the vastness of the universe, my own life was short. What did it all mean?

This place was just as overwhelming -- it was the kind of place that makes a person ask the Big Questions -- about life, about death, about the mystery of being alive.

I stared down at my thin brown hands. It occurred to me that I was a part of those questions. My very body was as much a mystery as this universe. Every beat of my heart, every breath in and out, my fingerprints, my face, my feet -- were a part of the mystery. I could ask, who were those weird aliens? But I could also ask, who are human beings? Who am I?