Age 13: "Do NOT ask for World of Warcraft for your birthday. It will eventually lead to you showing your best friend. He will get addicted, play it non-stop, meet some 35 year old psycho in California who has a kid, and by the end of your senior year he'll move to California to live with her and you'll likely never see him again. Take a high school programming class."
Age 16: "Don't be a moron and ask her out on the day she gets in a fight with her ex-boyfriend. More importantly, man up and ask her out in person, don't leave a note in her locker. Also, don't pursue the cute, nerdy girl who plays video games. Keep her as a friend, (that's all you would be during the 10 days of that relationship anyways). Also, GET A SUMMER JOB FOR THE LOVE OF GOD YOU WILL REGRET IT IF YOU DON'T."
Age 18: "Western is a great school and you'll meet a lot of really really cool people. If you have any second thoughts about Computer Science after the first semester, change your major. But still give CS a try, you will meet some of your best friends through that program. Don't fuck around your freshman year either, or by the end of it you'll have a bit of a mental breakdown and it'll all go to shit. Sign up for an early orientation time or all the good classes will be gone and your schedule will suck. Just do your homework. Also, call your parents more often."