Three levels, start to research
The levels are cumulative. Beginner needs nothing at all; intermediate assumes linear algebra and basic Python; advanced assumes you are comfortable with the intermediate material and want to work in the field.
Beginner
You have never touched quantum computing. This level uses pictures, analogies and probability — no linear algebra. The goal is that you can explain what a qubit is to a friend, and that you know what quantum computers genuinely cannot do.
Intermediate
You know the words. Now you learn the notation behind them: complex amplitudes, vectors, matrices and Dirac notation. You will write Qiskit or PennyLane code and run it on real quantum hardware, and you will understand Grover and Shor rather than just naming them.
Advanced
You are comfortable with the math and want to work in the field. This level covers quantum error correction, fault tolerance, complexity theory, Hamiltonian simulation and the variational algorithms that dominate current research — and points you at the primary literature.