Don't worry so much about SATs; they only matter in the absence of other things that make you interesting. Athletes are given a pass on SATs, as are people with exceptionally interesting lives, as are really good writers, musicians, or artists when applying to conservatories. So work hard on improving your SATs (two or three days of half a practice test per day boosted my GREs up like 300 points to 99%; if I had spent more time I'm sure I'd have done better, so just suck it up and study!) but work much harder on your writing and visual portions of your application. That's what really matters, and the further into life you get the more you'll realize how meaningless GPA and SATs are beyond getting you into undergrad (which is also usually totally meaningless, but that's another story).
Just living in NYC is a start. There are tons of ways to network there without even going to school. I have met grips and camera ops who took one class at a camera rental place, worked a few unpaid gigs on craigslist, and are now beginning to actually make a living. I met more people who did go to school, though, admittedly, while on set. NYU is great but insanely expensive and the NYU students I met for whom money was an issue uniformly said that the education isn't worth the insane expense, but it is really exceptional otherwise. Columbia is good, too, but it's not technical, and it might be MFA-only. SVA is very technical and people seem to like it. There are tons of others, some affordable state programs that are well-regarded included. Ask your guidance counselor. There are good schools across the country (I lived in Boston: Emerson and BU are not bad at all), but where you go to school determines where you'll work to a greater extent with the film industry than with other industries so if you like NYC stick with it exclusively or if you're dead set on LA go to school in LA (only if you can afford it!). I think I heard Ithaca had a decent program, too. I forget...
Unfortunately, each program has its different strengths and weaknesses and you won't know what really interests you until you're most of the way through, but intuition will get you far in choosing. A lot of people will argue that you should get a liberal arts degree rather than a more professional degree, but I'm not sure. Most BFAs offer a bit of both. I get mixed reviews on NYFA/Full Sail, which are exclusively professional, but most people seem really bullish/enthusiastic about them who've attended, which runs counter to the arguments I read that they're overpriced for-profit degree farms. But I'd try to go for a well-established university with a bit of a traditional as well technical education, even though the technical education is all that matters on the job and a lot of people working in film will tell you school is worthless. And a lot of people with no formal training will get jobs off spec work (youtube videos with high view counts even, now) that USC grads would just salivate over.
Also, writing/directing and working in film are two entirely different things. If you want to write and direct, live an interesting life and network and read. Storytellers need stories. If you want to make money, go to school for post (editing/vfx/etc.).
Visit everywhere you're considering going to and look at what connections you get after the fact. Look at the gear you have access to, the work the students are doing, and most importantly the network that you'll be launched into (internships matter, too). The community (students and professional network) matters most. And you don't have to go to school to work in film (it probably hurts more than helps in some ways), but if you don't know exactly what you want to do (edit, shoot, gaff, produce, act, write, etc.) you should give it all a try.
Also, don't expect to work as a writer or director, but you will get opportunities to direct in school. Take this with a grain of salt, btw, I am in the same camp you are...just much, much older, and by now probably much poorer, too.
