Hello /adv/ highschooler here. I just want to know what subject

Physics
You're gonna get a shit ton of math either way

Physics. No doubt.

What is your purpose for going to university?

>Education for fun with disposable income
Whichever you enjoy the most. Look into what higher levels of each will look like and decide which you're more interested in experiencing.

>Education for a degree in order to obtain a livable job
Determine what your end goal is here, and choose the major that would make it easiest for you to achieve that. Bonus points if your degree allows for a couple backup careers for if you change what you want.