For what it's worth, I failed OASC about 30 years ago. At that time I had a few hours towards a PPL which I'm sure was of little value. I failed because I didn't demonstrate that I had the qualities required of an officer. I would suggest that you take up a competitive sport, be in tune with what's going on in the world and be confident but not cocky. As somebody has already suggested, it would worth getting involved with something like Scouts/ATC etc. The RAF gave me every opportunity to prove myself at OASC and I messed up.