Your legacy begins wherever your success starts benefiting someone besides you.

For a long while success is entirely inward-facing, and reasonably so, since you were building something that did not exist. It becomes a legacy at the point where somebody else is better off because of what you built. That transition can happen much earlier than people assume, long before there is a large amount to give.

Ask who currently benefits from what you have made. If the answer is only you, find one small way to change that this quarter. Legacy starts as a habit, not as a final act.