You remind me of myself...
I was also about 13/14 years old when i first got the bug for flying. After looking at all of the information provided by the very helpful flying schools in my local area (Manchester) i realised that pursuing my dream of becoming a pilot at such an early age was, not pointless, but not economically viable.
You'll be looking at completing solo flights within your first 10 hours of flight training which (dependant upon how often you plan to fly) will most probably be completed within 6-12 months. You will however be restricted by your age and will have to wait until you become 16 to progress any further through the PPL course. If you spread your lessons out too much, say one every 2-3 months, you will no doubt forget things and you will simply need more lessons than you would if you flew more regularly.
Due to this, I myself decided not to start the actuall PPL syllabus with a defined flying school, but instead began searching for flying lessons that people were selling on Ebay (which are much cheaper than lessons at flying schools). I travelled to many different airports over the north-west including Barton, Blackpool, Sheffield City, Netherthorpe and Leeds-Bradford. As I was 14 I was able to log my hours as well as gaining precious experience at flying light aircraft at much cheaper rates. (I also managed to get a feel of many different types of aircraft too).
When i turned 15 years old i began studying for all of the groundschool subjects. I passed all of the exams within that year (year 10 at school - before the rigorous revising for my GCSEs came along in year 11).
A couple of months before I became 16 I joined a flying school at Barton aerodrome (not because it was particularly better than ay of the rest, just because it was the closest) and started to complete the actual PPL syllabus. On my 16th birthday I was ready to go solo with only 3-4 hours experience with my new flying school (due to my previous experience), only to be let down by the great British weather. After what seemed to be a lifetime of waiting, I eventually got my first solo out of the way and continued through the course.
I managed to complete my Qualifying Cross-Country (QXC) at the end of July (this year) and actually took and passed my skills test just last Wednesday (19th August). I am now just waiting until my birthday in September as I cannot actually get my licence issued until my 17th birthday.
Overall, the way I went about my PPL worked out really well for me. Whatever route you decide to go down to get your licence, you will no doubt become frustrated with the ever-dependent British weather.....aherrmmmm! But will in the end think that all of the effort was, in no question, worth it!
Good luck with your future flying career. I am personally looking into the RAF after I go through college as the Airline world seems like an impossibility to get into at the moment! With any luck by the time you are ready to move into the commercial world, this depression will have died away and airline recruitment will become much simplar.
I am hoping that my PPL will aid me in my application to join the RAF (it can't make it any worse can it?). I am hoping that they will see i have the aptitude for flying. Oh well, we'll see.
Good Luck to all you aspiring pilots.
Lukem08