Never forget your first client, the one who paid before you had any reviews. They took the bigger risk.

Early support costs more than later support. Whoever chose you before there was any evidence made a decision with no cover, on nothing but a conversation and their own judgment, and they stood to lose far more by being wrong than the people who arrived once you were established. That was a real act.

Say so, directly, to whoever it was in your case. Look after them when the queue gets long, and remember them when you are deciding where your attention goes. Loyalty backwards is rarer than loyalty forwards, and people notice it.