None of the above. Either one of the aforementioned options would be a tremendous waste of money for you.
Do you have any idea how advanced those programs are? It would be years before you even get close to fully utilizing them. And that's if you fancy yourself an editor. But in another post, you said that you want to be a director. Heck, for all you know, you may discover that your true passion is as a foley artist. Or a cinematographer. Without knowing your strengths and passions, it's way too early for you to make such a sizeable purchase, when something far less expensive will do everything you need it to.
Sony Vegas HD Platinum 10. Less than $100.
As far as basic editing is concerned (which is what you will be doing), Vegas Platinum 10 is just as strong as either of the other two. You're 15 years old; you've got time to figure out exactly what you want to do. For the time being, I think you should try lots of different things, see where your strengths are, and where your passions are (probably in the same place). As I mentioned before, unless you see yourself as specifically wanting to be an editor, you don't need the most expensive software.
I have CS5, and love it (but you wouldn't believe how much of it I don't use, and I've been doing this for many years). I've used FCP, and it's pretty much six or one-half-dozen of the other. But you don't need either.
Save your money. Use it to build a light-kit. Or to get better sound equipment. Or build a jib. You fancy yourself a director? Directors want jibs!
Sony Vegas. Excellent program for first-timers (because it's cheap), and it functions basically the same as the other two, so you'll be able to easily transition to them, if/when you're ready.