To a Younger Coworker: “When I was your age…”
Your younger coworker probably gets enough of this phrase from his parents, so do him a favor, and avoid bringing it up in the workplace. It’s understandable that you want to help your younger counterparts out, but this is the wrong way to go about it.
Instead of ever starting a sentence with this phrase, engage yourself in a more fruitful conversation if you’re trying to give advice. Ask your coworker questions and show interest, and only give advice if he asks for it. You can tell him how you “went about things” while you moved up the ranks, but avoid this phrase the best you can.