Question: how does your supply regulate / increase as your newborn begins to need more ounces if you aren't nursing? Does your body know "ok now it's been three weeks"?

Long version: I've been EPing since day 2 with my daughter and she is now a week old. I'm pumping 8x a day for 15-20 min and getting about 3oz total per time which is what she is now eating. As she eats more how do I increase supply? Does it happen naturally at the beginning or do I need to add pumps ?