I agree with Blacksheep, get the grades now and aim high. If you get offered technician 'cos they didn't think you were quite "officerlike" enough, take it and work your way up from inside.
As for the cuts, don't worry unduly, the RAF will always need far more engineers than aircrew, and do not get the same huge number of applications. Yes the standards are high and a bit of luck will do you no harm, but it's not unachievable.
G