Spotting at Newcastle......a good start.
Your ultimate goal to fly......excellent. The question is what is the best path to achieve it.
Stay at school, do well in the 'A' levels. Maths, Physics, & English at 'O' level with descent grades. Probably higher education so that aged 21/22 you have sufficient maturity to start with the professional training.
Obtain your class one medical.
Now the choice is Integrated or Modular route.
No advantage in doing your PPL just yet.
Try some gliding first. Visit ATC Newcastle.