Applications run from August through June, so you still have time to apply if you take the MCAT at the beginning of next year sometime. Just remember that it can take up to a month for you to get your scores back and seats can fill up quickly for early test dates. I'd check AAMC to see when dates are available to test. You probably should really get some shadowing done as well just to make sure that this is the career for you. Both of these things are possible depending on your schedule and depending on when MCAT seats fill up. Just know that studying for the MCAT can be very time consuming if you want to do well on it, which is beneficial seeing as that your MCAT score can greatly affect your chances of getting a scholarship. Also, schools will start to fill up in the spring, diminishing your chances of acceptance, but that doesn't mean it's impossible to be accepted somewhere. And try not to worry too much about having a gap year! It only gives you more time to make yourself a better candidate as well as relax a bit before what's going to be a very intense part of your life! If you won't have time to shadow or study for your MCAT next semester, then I would even highly recommend it so that you have time to focus on these two things.