Beyond programming, here's some of my favourite

*free* computer science resources that should help you get through uni and are great if you wanted to get ahead during the break!

Full intro to CS done by Harvard - completing this would give you a great head start before next year - I'm only about a quarter of the way, and it's amazing (remember to do the problem sets for the full experience!)

Introduction to the intellectual enterprises of computer science and the art of programming. This course teaches students how to think algorithmically and solve problems efficiently. Topics include abstraction, algorithms, data structures, encapsulation, resource management, security, and...

cs50.harvard.edu

Khan Academy crash course through CS - some high quality stuff here that goes broadly over the key points for CS theory - not too much depth here but there are links to explore further

Learn AP Computer Science Principles using videos, articles, and AP-aligned multiple choice question practice. Review the fundamentals of digital data representation, computer components, internet protocols, programming skills, algorithms, and data analysis.

www.khanacademy.org

OSSU - complete CS course of entirely free resources from top uni's like MIT based on the US curriculum - super comprehensive resource

:mortar_board: Path to a free self-taught education in Computer Science! - ossu/computer-science

github.com

Math needed for CS - series from 3b1b going over calculus and linear algebra (the 2 main math concepts at usyd atleast). Even if you're comfortable with calculus I still recommend the series as it's a much better explanation intuitively than I ever got in school. Also Khan Academy linked here.

Calculus:

Learn AP®︎ Calculus BC for free—everything from AP®︎ Calculus AB plus a few extra goodies, such as Taylor series, to prepare you for the AP®︎ test. Full curriculum of exercises and videos.

www.khanacademy.org

Linear algebra:

Learn linear algebra for free—vectors, matrices, transformations, and more.

www.khanacademy.org