WHAT IS A GOOD TIME TO START LEARNING SYSTEM DESIGN

Basically the title. For context, I am a 2025 grad, recently got internship offer from a decent company (off campus) and I am looking to upskill my DSA and CP skills to target FAANG level companies for full time roles and system design. What should I give more emphasis on and how do I go about managing my time ?

ANY ADVICE WOULD BE APPRECIATED !