Your age and lack of total experience are not in your favour. Jobs are scarce right now and the financial commitment required to complete all the training is enormous.
Whilst it is true to say 'if you want something enough...........etc' the chance of getting a job will be slim to say the least.
If you really feel you must persue your dream then at least have your eyes WIDE OPEN, budget for the wrong side of £25000, and accept that after training you may not get an airline job.
I do not want to pi$$ on your fire but at least you now know.
Good luck either way
JWF