It seems to me that you’Re being pretty hard on yourself. Most 16-year-olds (or even 30 year olds) never get that far. You should be proud. When I was your age I also set goals that were often difficult to achieve, setting myself up for failure. Sure, many times it actually worked. But not always. So ask yourself this: If the publishing world is becoming increasingly more difficult, how realistic is your goal of publishing at 16? Will it be the end of the world if you don’t get published until you are 18? Or 20? If writing is important to you, do it. The goal you set should be to get noticed (which I think you’ve already successfully done) and to eventually publish. Go to college as planned but NEVER give up writing. As long as it makes you happy, do it. If you are good, things will fall into place. Just maybe not at the rate you want.
And remember……the first Harry Potter book was rejected over and over again and first printed by a small publisher. Once that became popular it was picked up by a large publisher and now she is mega-rich. Every writer, no matter how good they are, is subject to rejection.