Nick,
I started young like you too, and I'm a professional artist now. Keep at it, you're a hell of a lot better than I was at your age! I especially like your architectural stuff and your portraits. The skating stuff is cool too. I had a friend in college who did a lot of skateboarding photos, he did his graduation project (for his Bachelor's degree in fine arts) as a series of skateboarding photos. I'd never have thought of doing them in medium format....but the square format works well for yours. I'm jealous of your camera collection too! You have some awesome old cameras. I used to have a Mamiya TLR too, but sold it a few years ago. Regretted that for a long time. Anyway, great stuff.
I'll give you some advice, learned the hard way by my own experience:
1) Don't let anyone try to make you change your style of work...it is great as it is and will only get better with practice.
2) If you go to college to study art (and you should), make sure to also major in Business (get a double major) so you'll know how to operate a business and make a living as an artist. Don't let them romanticize art and make you think money is evil. It isn't, you need to eat too. The whole art world is a giant parasite that makes money off our work while keeping us poor. Art is a business. The gallery owners know it and take advantage of the fact that few artists know it. A business degree will also get you a job, should you need one (and you will for a while until you can make enough to live just off of art sales or commercial photo work).
3) Don't cut your hair, no matter how much your parents bug you about it! LOL I'm 33 yrs old, I have a college degree, and I have an 11 year old son....but my dad STILL keeps telling me to get a haircut!