in most cases, the "set back" for an undermount or self rimming sink is 4 inches.
this is measured from the very front outside edge of the stone, to the front
inside wall of the sink bowl. The 4 inch dimension can vary though, as sinks
do have variation in the overall depth (from front to back) but (around) 4 inches is kind
of the standard in the industry.

hth

kevin

Thanks, Kevin.

After reading your reply I realize I probably should have noted that my sink is a drop-in. Would it still be roughly 4" fron the front outside of the countertop to the front inside wall of the sink anyway?

I would say the minimum possible. The further back it is, the more you have to reach or lean into it. Mine is a little less than 3". I had it pulled as far forward as possible, but it is an undermount which means that the rim can sit on top of the cabinet box and overlap. Better love your sink though. ;-)