I don't mean to be snarky, but how was your data structures knowledge then? He asked "Is there some requirement that ML _must_ be an advanced topic" and I list

I don't mean to be snarky, but how was your data structures knowledge then? He asked "Is there some requirement that ML _must_ be an advanced topic" and I listed a few prerequisite pieces of knowledge that make it fairly advanced. You may learn those prerequisites in a different order but they are required before you properly tackle machine learning without cargoculting through it.