I'm guessing this is your first car? I would suggest not buying a skyline at all, get a little run around until you get your full license. Skylines are expensive to run and maintain, plus being young you probably wont have a lot of money so buy a cheap car and save save save.
Also do some defensive driving courses, go on some cruises, meet and talk to people who own skylines. Take 3 years to work out exactly what you want and what you wanna do with it. Cause 3 years is not along time and you'd be surprised how much your driving matures in that time.