Look, I agree with everyone else that you need to chill, enjoy high school, and get into college before getting all freaked out about all this, but some general advice:
First, there is an "S". Make sure you get the school's name correct.
100 clincal hours
50 shadowing
3 years research
All of these are going to depend on the quality. You have to be able to talk about what you did, saw, learned, etc. rather than just the fact you did them for X amount of time.
This is difficult but not impossible. The most important thing for you to do as a high school student is establish good study habits and discipline before getting into college. I am sure you think you have good study skills - I though I did too in high school - but you may not have been tested like you will be in college courses. Learn HOW to study now and carry that into undergrad. Also, when you get into undergrad, try to pick a major that interests you, even if it isn't a traditional science major. You will do better if you are interested in what you are learning.
Don't think about this yet. Take undergrad courses that give you a good foundation in the sciences and take biochem before taking the MCAT. Otherwise, you will just have to study and take some practice tests to see how well you do and how much you can improve. Aiming for a number right off the bat is bad juju and is only going to set you up for disappointment and frustration.
Finally, once you are getting closer to applying to medical schools, you can check out each school's stats. Come back in a couple years and be overly obsessed and stressed then, but not now.
