Learning is ever in the freshness of its youth, even for the old.

Learning does not get old the way the rest of it does. The experience of understanding something for the first time is identical at seventy and at seven, which makes it one of the very few pleasures that does not diminish with repetition or with years. Nothing about age closes this particular door.

Start something you know nothing about, and pick it because it interests you rather than because it is useful. Accept being a beginner in front of people much younger than you. That discomfort lasts about a fortnight, and the freshness lasts as long as you keep going.