>>1 I really don't know how things work at your country about college and grades and stuff, but I'll tell you this, being pressed to decide your life's path from the age of 18 or 16 or whatever, is if not impossible, it is really difficult.
I have been there and I have those things to say to you and whoever else has the same troubles.
First you have to know that you won't have only one job in your life, you will change many jobs, and most of the times they will be completely irrelevant to each other.
Secondly, exactly because of the first fact, I recommend you to choose studies that will work as a platform to build your future on. What I mean is that try studying something general,like economics, sociology,or stuff that at the first state are not too specialized. In this way when you will be a little older you will have more experiences and thus more info to base your choice on.
Thirdly working at a local store from your 16 would be really helpful. It will help you understand how things actually work on the market , and as I said before it will give you experience!
and last but not least I can see that your choices are based on your life till now and a bit influenced by maybe some games you play or movies,TV series and anime you watch. Please try not to be too influenced by those. I don't say that those jobs you want arenot good,hell they are facinating. Yet when you will grow older you might find out that you are not as awesome as L as a detective or as House as a doctor and youmight find that this thing is not for you.
All I'm saying is that try and look a bit out of the familiar environment you have,because from personal experience I wanted to be a doctor while watching House ,but now I know I can't stand blood. Also I used to play shooting games but in reality I'm a lousy shooter and a chicken when it comes to real guns XD.
so yeah I made my point...and I hope I have helped.