Learning to drive, swim or cook later than your friends just means you’ll actually remember learning it.

Learning something at four installs it below the level you can see. You can swim or ride or speak the language without any idea how. Learning at sixteen is slower and stays conscious: you know which part was hard, what the breakthrough was, what you were doing wrong for the first month. That makes you worse at it for a while and far better at teaching it.

Write down the bit that is hardest while you are still in it. Later you will be the one who can actually help a beginner.