If I could send a message to myself when I was a kid, to blow my own mind, here’s what I would tell myself:

One day you will own several computers known as “laptops,” the least of which is more powerful than the biggest most bad ass mainframe under the control of any company or government.  You will own a telephone/movie and music player/computer that can wirelessly communicate with anyone in the world who also has a similar device, which is pretty much everyone.  That telephone/computer will be so small you can carry it in your pocket.  It will have enough “hard drive” capacity to hold every song on every single cassette tape you own, more processing power than your IBM, and better resolution than your monitor or television.  It will be able to pinpoint your location anywhere in the world and give you real time directions to anywhere.  You will have cable TV that plays Doctor Who at least three times a day.  You will have a machine that will automatically archive those shows for you.  Your “laptops” and phone will be able to access something called the internet.  It’s like a BBS system – only nearly every computer in the world is interconnected.  You will be able to look up any fact about anything at all on your phone.  There will exist affordable robots that can make anything you wish out plastic, just draw it on your computer and send it to your robot.  You will own TWO of them.

Wibbly wobbly timey wimey.  (That will make sense one day).