I would take a slightly different perspective than Reluctant...But the advice given is really sound....I cannot advocate strongly enough getting some decent qualifications and then getting a job.
There is a real desire now to just jump into it at the earliest opportunity - understandable, but every £1 you can pay yourself towards your own training is probably worht close on £2 of borrowed.
If I were you, I would look to get the best GCSEs and A levels you can (I personally would do a degree as well in a profession if you can) work until you are 26/27 and then do the training....you will graduate around 28 years old and if you're sensible, with virtually no debt (from either route) and the whole aviation world in front of you.
There's a whole bunch of people who have just gained the cheap plastic blue book (me included - although I'm very fortunate and debt free...) who right now are either feeling very grateful indeed they're not in debt, or frankly speaking - ****ting themselves big style. If you were to graduate just at the time of a downturn like this one, as I did - believe me, you will be SOOOOO grateful to not have any debt!