When you look back at the advice you gave yourself, it is surprisingly spot on even if it didn't seem so at first.
I am writing this letter to remind you that life is what you make it to be and you need to stop being so serious about what you think you need to do to become successful. You should make every moment count, read every single book in the library, facebook as many friends as possible, apply for jobs around the world on a daily basis and see if you manage to snag something cool, love daily, and write as much as you can to document the days you feel inspired, thoughtful, or lazy. Use your time wisely and be thankful that you have the time to waste away watching youtube videos, reading, or blogging. Later in life, you can be serious. However, for now, you should endeavor to make life more interesting.