I have never tried steeping the day before, but I have heard bad things about mashing the day before and boiling the next day. It can easily go bad in a hurry. I heard that you can sometimes get away with it, but eventually you would end up throwing out a batch. Steeping would be similar, but just lower gravity.
When I extract brewed, I just heated my boil water to 162, turned off the heat, steeped grains for 20 minutes and removed spent grain, continued heating water and added DME / LME.
It only took an extra 20 minutes or less as I even started heating before removing the grain as long as my temp wasn't over 170 when I removed them. You will start getting tannins from the husks if you steep over 170.