if I choose to get sponsored by the Army
I think it's the Army who will do the choosing!
You've set yourself some very high targets: Imperial Aero, RMAS, pro pilot. Good luck. I can say with the benefit of experience that it will be a long and tough journey - I followed almost exactly that path albeit with a blue uniform. You will have to work harder than you ever have before, and there will be setbacks along the way, but if you make it (and that is not a given) you will rightly feel a great sense of achievement. There are quicker and easier routes to the flight deck but I'm glad I did it my way.
A few top tips that I strongly believe in:
Spelling and grammar isn't just for special occasions. Most people of professional calibre knock out the Queen's English by default, all the time, without it being any particular effort. Txt spk and lazy English is generally very negatively received in the institutions you are targetting.
Sometimes you just have to wind your neck in and play the game. You may think that the person assessing, interviewing, instructing or examining you is an out of touch old fool with an attitude problem and the wrong way of doing things. If you want to be successful you'll need to play be his rules. If you expect them to adapt to yours you'll be in for a disappointment.
First impressions count more than you would believe - even those that you think are informal, unassessed and off the record. Those that make a bad impression don't get an interview / callback / offer.
Don't take these as specific criticisms of you - they are just a few thoughts that will increase your chances of getting what you want (but are often not appreciated by people in your age group).