I suggest reading and digesting this document which is the best guide I know to pilot careers - note that there are many different types of pilot, not just as an airline pilot.
https://www.airpilots.org/file/499/p...-final-web.pdf
At your age, you're in the position of being able to position yourself any direction you want - and do consider that with the right effort and motivation you could aim at being a military pilot flying a Typhoon, Apache or Lynx which even in my 40s sounds far more appealling to me than locked into an airliner cockpit managing systems and not allowed to talk to the passengers any more: and certainly in my teens, well who wouldn't want to be a fighter pilot? (Or if your views are more humanitarian, search and rescue pilot?)
Think also about the things that you can do now to position yourself. I'm certain that there are Air Cadets and Air Scouts in Liverpool, there may also be a glider club or two around with junior or cadet options.
For what it's worth, I did a degree in aeronautical engineering, then paid as I went getting pilot licences as an aeronautical engineer. But I just love the technical side of aviation - rather than being hung up on *just* wanting to be a pilot. But, I've yet to regret that combination. On the other hand, most people do prefer to be just one thing.
G