09/04/2013 03:38 pm ET Updated Nov 04, 2013

Growing Up but Never Growing Apart

Tayler Held

Dedicated to Sadie Held

I was scared. Knowing my twin sister and I were going to be separated soon was terrifying.
It must sound like we are conjoined twins. We might as well be. Sadie is my best friend, and we are what are called "mirror twins," meaning that if we stand across from one another it is like we are looking in a mirror. I am right handed she is left. My heart is on the right, hers is on the left. Her part in her hair goes left, mine goes right. You get the picture. About 25 percent of identical twins are mirror twins, a term used to describe identical twins' physical features.

Sadie is my rock. We recently were separated from one another, and are realizing that while we are growing up, we will never grow apart. She lives about three hours away in Missoula, Montana, and moved to get a "head start" before she begins college in the fall. The hardest thing I have ever done was tell Sadie -- my best friend -- goodbye. We have been together for 18 years, through thick and thin. Graduating high school recently, on our 18th birthday, was bittersweet. I was finally realizing how little time we actually had left together before Sadie's move. And how many years we have already spent together.

Sadie's been a huge support during my toughest times. When I was diagnosed with epilepsy, and later on when she was, we were both there for one another. I was diagnosed when I was 12 and she was diagnosed when she was 13. Sadie had broken her leg, and while she was in the hospital she was given a medicine that induced her seizures. Sadie's epilepsy isn't as serious as mine and she has only had one grand mal seizure. While I had a more difficult experience, and frequent seizures for several years, it was still nice to have someone understand how I felt.

I have always spent most of my time with Sadie. When we were younger, I don't think we quite understood how close we actually were. I would have a "best friend" from school and so would she, but my dad would always say, "Your sister is your best friend." We would disagree -- but it turns out dad was right.

With just one look we both know what the other is thinking. People ask if we have ever experienced "twin telepathy." I don't know if I would go to that extreme, but we know each other like the back of our hands. Sadie has always been there for me. I sometimes had a tough time in school when I would hear other students make fun of seizures. Epilepsy isn't something you can see, so they often didn't know they were making fun of problems I struggled with every day. I would get so upset, I would cry. And when Sadie would find out you could tell she was furious, but all she would ask is who they were. I don't know if she did anything but she's always protecting me.

I'm so proud of her living on her own in a new apartment, but I miss her. I can't wait to also go to Missoula to start school this fall to study art. I'm excited to begin college life, but I'm ecstatic to see Sadie and live in the same city (though not the same apartment.) I cannot imagine what life would be like not being a twin. It would be too ordinary! Sadie makes my life more loud and fun, and she's more outgoing and brave than me. I am seven minutes older, but Sadie acts like she is my older sister (she wishes!) I look up to Sadie though, and I always will. She is so inspiring.

I am so thankful to be a twin, and I appreciate Sadie for all she has done for me, whether it was giving me advice or just driving me around everywhere (due to my seizures, I cannot drive.) I know I could not have gotten to where I am now without Sadie. I look forward to seeing where her future takes her and where mine takes me. As we grow up and "spread our wings" I can't help but get excited. I am already so proud of her; I just wonder what she will do next! After 18 years together, I'm not scared of being apart anymore, but eager to see what the next ones are like.