Pick something that interests you and start learning about it. Hacking is about understanding how computer system operate, and then making them do things they are not supposed to through what already exists. As far as hacking goes, knowledge is key. Start learnign everything and anything that interests you about computers, and drop all your expectations right now. If you work hard, and have a little bit of luck, you might actually be able to pull off your first hack in about 2 years. But that's only if you are serious and you bust your ass in all your free time learning this stuff.
correction: The hacking you are talking about is what I defined it as. there are many definitions of the word, and I hope nobody decides to play semantics here :p