Do I have a leak in my gas line?
3 minutes is really not that long the regulator had to fill the control after its valve and to the pilot if you had a leak 30' away it would have taken much longer, gas lines after the main gas regulator are only approx 3/4 of a psi, very small so it can take a little time to fill. The way gas lines are tested where I have installed them is by pressurizing the lines with the local shutoff at the stove, fireplace, furnace turned off and the line pressurized up to 30 psi, the inspector notes the pressure then inspects the work if the gauge drops you fail. We usually do this pressure test the day before inspection and make sure there is no drop overnight, not just the 15 -30 minutes the inspector is there.