Become a Raf pilot without a degree?

I am planning to join the air cadets at 15, then get a PPL at 17 and try for the raf as a pilot at 17 and a half years of age. What are the possibilities that i will get in? If i don't, can I try again at 21 after getting a degree. And also can you get a degree whilst in the raf? I am currently thirteen - set 1 for all subject and fastest runner in our year.