'Love affair with small dogs' - Common app extracurricular essay

My love affair with small dogs began when I was eight years old. My parents took me to a pet store, and oblivious to the world of puppy mills, we purchased our first pet. We soon discovered our Pomeranian was sick with the Parvo virus, most likely negligence on the store owner's part. Since then, I have learned that not every relationship with a pet is as happy as those depicted on the commercials for dog food we so often see on television. In my time volunteering at a local animal shelter, I have interacted with dogs that come from many environments. The animals there have taught me the importance of the seemingly small actions- the position of my hand, the tone of my voice. Every aspect of my body language leaves an impression on who I am to a dog, and in turn I have changed the way I act in everyday life. I now pay attention to the little things I do and others do- and my experience has brought me one step closer in discovering what kind of mark I want to leave in the world.

Any help with grammar/overall comments about content is greatly appreciated!

The first two sentences doesn't really tie in with the rest of the paragraph.

Thank you, I've edited it! Is the flow better now?

In my time volunteering at a local animal shelter, I have interacted with dogs that come from many environments. Not only have I had the opportunity to give the animals there a better quality of life, but they have also taught me the importance of the seemingly unimportant actions. Whether the palm of my hand was facing up or down could lead to a dog frightfully anticipate an incoming strike, and a slight straightening of the back could indicate self-confidence and command respect from an animal. Every aspect of my body language leaves a mark on who I am to a dog, and in turn I have changed the way I act in everyday life. I now pay attention to the little things-the way a person walks or where a person looks when talking, and I try to see how that changes my impression of them. Now, whether I am presenting in a front of a class or whether I rushing in the halls trying to get to my next class, I remember to stand a little straighter, because it can make all the difference.