Dear little brother,
You are about to experience the best things in life. You are getting older, growing up fast, and making memories every day. Try to take life day by day, and remember that it's OK to make mistakes. In life there will be many ups and downs, but that just makes you who you are.
Respect your elders.
I know that while you are in middle school and high school things can get tough, but always trust Mom and Dad, they really do know best. I remember in high school it was so hard for me to understand that, but respecting your elders and being responsible gets you so far in life.
Always take time for school.
Even though experiencing new things in life can be amazing, make sure you always keep up with schoolwork. Studying is so important, and good grades will get you so far in life. Remember to always focus on your future, while still living in the present.
Be respectful to everyone you meet.
I know I said to remember to respect your elders, but respect those all around you (including yourself). Respect girls, always make them feel important, and respect your classmates. I know that sometimes in high school it can be hard to fit in, but never be rude to anyone, even if your friends are. It'll be worth it in the end.
Be confident.
I always struggled with confidence, and I didn't do as many things as I could have in high school because of that. Don't worry what others think about you, and be yourself. Be loud (but not too loud) and express your opinions. This will get you so far in life.
Don't grow up too fast.
Even though adulthood looks exciting, I wish I was still your age again. Live life to the fullest, because one day you will not have as many opportunities as you do now. Try to join as many clubs as possible, make friends with others that you never thought you would be friends with, and try new things that maybe you never thought you would do.
You are about to start a whole new world and live a whole new life in the next few years, and it is important to see the amazing value in that. Never forget about your family, but also be sure to make new friends and make amazing memories. You will do amazing things one day, because you are already doing so many incredible things now.