10/13/2014 04:06 pm ET Updated Dec 13, 2014

The Most Important Lesson I Learned As a Writer

It was the perfect first spoonful of summer 2013: a classic Memorial Day weekend. I was sitting outside on a patio couch next to the pool in our Philly-suburb house. Sun shining, Coke cans lining the edge of the shallow end. A rough draft of the first story I wrote for my debut book, The Twin Connection, pulled up on my iPhone screen.

I was sandwiched between Hannah, my twin sister and co-author, and my Uncle Dan, who had come with his family to celebrate the holiday. I know that whoever might be reading this probably does not know Uncle Dan personally, so I will tell you straight-up: Uncle Dan is one of those people whose opinion you trust. You want to tell him about all of the things that go on in your life, just to see his reaction. And his reaction has the power to either reaffirm or discourage every word that comes out of your mouth.

So, naturally, I wanted him to read the first five of what would eventually be 162 pages of stories. Before then, every idea Hannah and I had for the book, every memory, every moment, was nowhere but in our brains and on the notes page on our phones. I was literally nervous as I watched him scroll with his thumb, leaning far back in his chair with a thoughtful expression on his face. Five minutes seemed to last five hours. Then he handed it back.

"It's very personal," he quipped. Then he gave one of his infamous, prideful, smiles -- arms crossed - and watched for my reaction. I paused for a good three seconds. Suddenly, I was terrified of the whole book thing -- it hit me for the first time just how much of my life I was sharing. All my stories scrambled around in my head, and I cringed at the thought of them being too personal. I thought of everyone I knew and how they might react as they turned the pages for the first time. Then I caught Uncle Dan's eyes again, still staring at me. I couldn't think of an intelligent way to explain myself, so I just blurted out the only thing I could come up with.

"I know. I think it has to be."

That was a year and a half ago. Now, that very story is a part of an actual book -- front cover photo shot by a New York City photographer, back cover filled with blurbs. And more than ever, I see the truth in those eight words spoken underneath the almost-summer sun that day. I can feel it. In fact, it has become my motto. Tell the truth, the whole truth, and nothing but the truth. It was the foundation that built our publisher's pitch, and the force that kept us going through re-writes, long editing sessions,and design decisions. Nothing mattered other than the meaning of the stories. At one point, toward the end of the writing process, I went through the entire manuscript again on a shameful mission to take out personal details of my thought processes during the emotional stories. I literally did that! But whenever I deliberately left out or added even a single detail, whether it was to tone things down or spice things up, it never stayed that way for more than a minute. I felt compelled to go back and change it, because I knew I had no other choice. There wouldn't be a point to anything that Hannah and I wrote unless it was 100 percent authentic. We wouldn't really be telling the story. It would be incorrect, and I'd have to live with that for the rest of my life. So, yes, my sister and I wrote a book at 17. But I also learned a lesson that will influence every single thing that I will write in the future, and I am sure that it's for the better.

My Honesty Policy.

That is what I am most proud of.