Option 1. Pass five of your exams and study 'to A level standard'. Get an application form, fill it in and wait with fingers crossed. Play the interview game and hopefully you'll become an ATC student!
Option 2. Pass less than five of your exams, get a job as an ATSA or Sim Pilot. This will give you a decent grounding for a couple of years and THEN you can do the application/interview thing!
Good luck!