As a candidate who has just passed the AIB and is starting BRNC February without a degree, military history or anything of the sort I can tell you it's very doable. They are looking for people not statistics, that being said all of the other candidates at the board were graduates. I was a school prefect, was in the ATC for a short spell and led an Airsoft team. Nothing too impressive, a lot of the others had sporting achievements. I didn't know I wanted to be in the Navy up until the moment before I applied so I didn't tailor my life to it, I suggest you start your application now and just 'live a little'.