Year 12s: what will be the first way you research your future options? >>

Career:compsci...

I have always been very interested and passionate about computer science and knew i was going to a degree(s) in it and become a software/hardware engineer/computer scientist(forgive me for incorrect syntax if applicable)...

Recently i have been reflecting upon my choice and confirming that is what i want to do for the rest of my life...

I already know that is what i want to do but as i said i am just confirming so...

so as a result of this i have a few questions to ask:

(FYI,i do computing at GCSE,i have done several computing related and programming related stuff outside of school and have a predicted grade of all A*'s and 3 A's and do loads of other Extra Curricular,MY GOAL IS TO STUDY COMPUTER SCIENCE AT CAMBRIDGE PREFERABLY)
Have any one of you gone into this field and do you find it rewarding?
Are you in an office/cubicle most of your work-life?
I would like to work in a large firms like apple,google,etc...,Is this possible or too far fetched?
Is computer science at Cambridge too far fetched based on the info. above?
Is it a very competitive course like medicine?

Any other advice will also be greatly appreciated...Thanks!