64 and jenny, I'm also reminded here of the "Pleeb Summer & 4/C Stories" of mostly "designed continuous failure". IF you are selected to attend, you need to ask yourself seriously, can you, will you, persist in the face of continued and unabated adversity until you've overcome all obstacles? Of stretching your limits well beyond where you, yourself, would give up trying? Can you continue to persevere in the face of all this day after day? Remember, this is not about just getting a good college education, although it is dependent on getting into one of the best colleges. Its much more then that. The application process is designed to sort out the "isn't that good enough" types before they get in. If you think you "have it in you", you can't quit at the first rejection. Or the second for that matter.
It only gets tougher once (if) you get in. I'm also guessing here that many of these OP's haven't yet begun to approach the very daunting application process. The one after the preliminary application. Fill out the application, and another application, get medical clearance, go again for something else, get physical clearance, get MOC nomination, teacher recommendations, and (I think) the best part, background checks. I'm always surprised by the "but I was only a little bit busted" comments. Your academics, your PSAT, SAT, IQ, etc, test scores are only a small (albeit important) part of this journey. A rejection in these other areas could mean the end of the application process (understand the 3Q'd process). No single part of it is easy or the final answer.
I think for high school kids the hardest part might be learning that standing out might mean not fitting in, that what gets you into the "clique" might keep you out of the running. I think the parents know what I mean here.
This is not an easy road to travel. A very small percentage of high school kids consider this course of action. However, for those few that do there are many high schools out there. So even if you're a stand out in your school you must stand out in the crowd of 17,000 other like-minded individuals thinking they can get one of only 1,200 slots, all of them strong students. I'm not good with math but those odds are pretty slim to start.
Bottom line, jenny said it, get stronger scores, keep at it, stay focused, and learn more about what the SA's are looking for (I don't think she said all that, but..) And remember, you are looking at last years, or older, qualifications, they keep getting tougher as the candidates keep getting better. Last years qualification may not be next years qualifications.
And good luck.