Do a degree because you want a degree in that subject, or a career in a subject that feeds.
Learn to fly because you want to be a pilot.
Don't conflate the two. Apart from the USA where lazy airlines use low quality "associates" degrees to save them bothering to do any aptitude testing, the rest of the world doesn't care if a pilot has a degree.
What you do at school shoudld feed the ability to study and pass your professional flying qualifications. The actual grades are basically unimportant. Learn maths, science (especially physics) and English to a good standard because you'll need those, and good grades will prove that. But it really is not about the grades or school qualifications.
And whilst you're young, just find any opportunity to engage with aeronautical hobbies. Military cadet schemes, gliding clubs, aeromodelling, volunteering at an aircraft museum - anything that's open to you.
(For the record, I'm a university professor who also holds professional pilots licences and teaches flying. I live and breath these questions.)
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