To my baby brother,
I know you aren't a baby anymore, but in my eyes you always will be. I'll never forget the one home video right before I found out I was getting a sibling and Mom asked if I wanted a brother or sister and I told her "never". She tried to convince me that a little sibling could be fun and I just kept telling her that I would never want a sibling. While you sometimes make me want to stick by that answer, the majority of the time I am so happy that I have you as my little brother.
I remember when you were born and getting excited that you were finally here...until you started getting more attention than I did. I was annoyed that I was no longer "the baby" and everyone was giving you presents simply for just being born. While that alone was enough to make me want to send you back to wherever you had come from, I still made sure every visitor held you properly and didn't hurt you. And that is something that'll never change.
I will always be there to look after you and protect you (God help the first girl you bring home) no matter how old you get. Whenever you feel alone or need anything at all, I want you to know that I will always have your back. I also want you to know how proud I am of you. You have so much more learning and growing to go, but you've already made me the proudest sister in the world. You are such an intelligent, caring, compassionate, talented and loving young man. I hope you never lose these characteristics and keep inspiring those around you with all these qualities and how grown up you are for your age.
Lastly, I want to thank you. While sometimes we can literally be beating each other up for hours, it is the fact that you can make me laugh until I cry just minutes after that is important. Thank you for always being my best friend, my partner in crime (the crime typically being a prank against our parents) and for allowing me to help you grow and learn. You have taught me so much about myself and even though I told our parents I didn't want you, you have proved time and time again that you aren't so bad after all. Besides, who would help me get through our parent's and our family's crazy antics?
I hope I have been someone you could look up to and have set a good example for you. And if you say I haven't been, just remember who can show future girlfriends embarrassing baby pictures and selfies that you've taken. I love you very much little brother and hope you never, ever forget that.
Love always,
Your big sister (who will always be way cooler than you)