hi,
Yes it is very possible. I am currently in 6th form, and am a level 1 qualified coach, doing football in the community with the local club, and doing work at schools around the area. However, it is not as easy as many think. I know people say this all the time, but you need to gather as much experience as possible. Sounds strange, but i have been coaching since the age of 13! I have been coaching kids from the age of 5 to 18 in the 5 years i have been coaching, and these experience have been invaluable. I have been able to manage my time so i can work on school work, and coaching. Im sure you will find it very hard at first to fit things in, like i did, but it is well worth doing. One thing however that i would strongly advise is if you currently play the game, cut down on how much. I used to play each morning and afternoon on saturday and sunday, and trying to fit that in with school work and coaching was simply impossible.
Hope the advice helped!