Congratulations Andy - Am chuffed for you. Its no mean feat getting in these days.
Always wondered what you were going to do after your proffesional football career
My advice would be keep your ears open, keep your head down, your nose clean and always answer instructors / officers "Sir" or "Ma'am" (unless you are told different). In other words common sense stuff
Basically just enjoy it as much as you can and if you want to get drunk at the weekend - do it on a friday night if possible, not a saturday night - cos then you will have plenty of time to get refreshed / study before monday morning comes round again.
Remember that somedays will be extremely tough but at the end of the course you will feel on top of the world.
So long as you dont do anything catastrophically stupid, such as spark out one of the instructors, or wear your BA set the wrong way round (yes I have seen that done) or break a fire engine they won't fail you.
Remember to be enthusiastic, attentive and open to receive critiscism from the instructor team and you will have absolutely nothing to worry about.
BEST OF LUCK!