Go for it mate, Gcses are always useful , and earning some cash too , wish i had that situation when i was at college !
Keep on at the AFCO , i did and i think it made my interviews more of a formality, I was that " keen bloke " who wants to join the regt, When you make it into the RAF remember that your pay check is all yours no more deductions to be taken , food and room paid for , you will never go hungry, you can save save save , join a flying club and get your PPL,
Good luck and keep the faith
Ben
Per Ardua