work experinace...

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...

I am currently at the start of Y11....

IS WORK EXPERIENCE NECESSARY FOR COMPUTER SCIENCE AT A UNIVERSITY LIKE CAMBRIDGE?

ACCORDING TO FRIENDS AS IT IS NOT A VOCATIONAL COURSE,IT IS NOT REQUIRED OR EVEN USEFUL?

Finally,Where exactly would you do Work experience?
are there any age limits?
how much do you need?
what else can i do to show my interest for the subject?

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