Hey Fion, in my humble opinion, I think you really should just go ahead and try!!
If I wasn't mistaken, Emirates will allow you to pass those stages and hold on your application till you reached 21. And if you managed to make it to the final and having to wait for their response from faraway Dubai, you'll already have hit your 21st!
Is anyone going for this open day Emirates is holding? We could all meet together and give each other some moral support! Yea yea!