Well, yes you have a chance. No one has said that it is impossible for you. There's just been advice on what has happened to other candidates.
Would you look upon us kindly if we said "sure, crack on, have a go" knowing full well that a failure at Stage 2 = no more chances at NJE cadet scheme?
To compare, I bought a ticket in the Euro millions. Sure, I have a chance, but look at the odds. However, my Aunty did win the lottery 30 years ago. So, you spend some time reading every thing and have a look on the Oxford forums as well.