I've just finished my A-Levels I'm Irish myself I'm going on to be a commercial airline pilot, well thats the end game.
I done 11 GCSE'S I've 6A*s and 5As main ones are Maths Physics and geography will help i always hard although i never done it. I done Physics and maths at A level A and B in them and history also.
If you're looking to train in the UK theres Oxford and CTC, i was accepted into both of them however you don't need A-Levels to get into them they do their own entrance exam on maths physics and hand co-ordination tests plus interviews they're around 90k plus you've an airline training on top of that at 30k+ .
I personally have chose to go to America, theres loads in the states Aerosim, Pheonix East. They're around 60-70k however your license will be different, you'd need to change it if you wish to fly in the UK. If you're pretty smart and have the financial backing go to Embry Riddle, thats were I'm going to train and earn a degree and hopefully get a green card.
And salaries vary in the US 20k till near 200k at captain in the emirates. I've family who've been pilots for many years, its a tough job its not like the virgin add where you've 9 air hostesses dandering behind you don't be under that illusion its demanding and its expensive. I was brought up as a child flying C172/152 i could never imagine myself doing anything else but its not for everyone
hope that helps