What's your advice to me as a 18 year old?

Do what you want to do and do it soon. Once you get established in a job or a relationship or a house or what have you, it will be too late to, say, backpack around Europe, or run off to Hollywood and try to become an actor, or whatever it is that you dream about doing.

Enjoy being young while you're young, because it passes away in a snap of your fingers, and the biggest regrets will be for the things you didn't do when you could.