Where shall I start? (16 y/o wanting to become quantum physicist)

[yjjiang]

Physicists generally fall into many categories these days, like condensed matter (formerly called solid state) physics, nuclear physics, high energy (formerly called particle physics), astrophysics, plasma physics, geophysics, acousticians, and perhaps a few other branches. Most of these branches use quantum mechanics as a tool. Almost no physicist (perhaps none) is called a "quantum" physicist.
Physicists mostly lead a life full of challenges, whether they end up in a field where quantum mechanics is used often, or not. You can be motivated by many life stories of people who engaged this exciting career. In addition, many mathematicians, engineers, and scientists also learn quantum mechanics, and end up in satisfying careers, as well.
As others have stated in this forum, you will need good grades in all scientific subjects in school, including the life sciences like biology, and all mathematics courses. It is not a good idea to focus too early on "quantum physics" because it may blind you to opportunities where your strengths and interests may lie. Instead, try to regard all sciences with fascination. Seek out motivating teachers, and learn from them.

I believe this is the best advice. In addition, we probably need a lot of quantum computer (QC) programmers in 5-10 years. I'd think a high school student who has learned some Python should be able to start learning QC programming.
https://qiskit.org/learn/
The math needed is not that much to start programming. Quantum theory is easy when you know how to work with the abstract mathematic symbols but is hard for people to understand intuitively.