Start here: https://youtu.be/F_Riqjdh2oM
You don't need to know quantum theory necessarily, but you will need to know some maths. Specifically linear algebra.
There are a few youtube courses on linear algebra
For a casual set of video: - https://youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFit...
For a more formal approach:
- https://youtube.com/playlist?list=PL49CF3715CB9EF31D
And the corresponding open courseware
- https://ocw.mit.edu/courses/18-06-linear-algebra-spring-2010...
Linear algebra done right comes highly recommended
Isn't there a Python library that abstracts most of it away with a couple of gigantic classes with incompatible dependencies?
+1 for 18-06 and Axler. Another, more concrete, option (not sure how much it will help with quantum theory) is Stephen Boyd's "Introduction to Applied Linear Algebra" available online here:
https://web.stanford.edu/~boyd/vmls/