Comment by fasterik

Start with 3Blue1Brown's "Essence of Linear Algebra" series https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2x...

Axler's "Linear Algebra Done Right" https://linear.axler.net/LADR4e.pdf

Nielsen and Chuang's "Quantum Computation and Information" Chapter 2. (Available online, but legality depends on where you live)

If you're interested primarily in QM rather than linear algebra, I'd recommend not working through all of Axler, but instead using Nielsen and Chuang to learn about qubits and observables, and using Axler to fill in the gaps.