I would paint the walls off white.
Remember that the sun travels in a east, south, west, direction.
Since the wall with the most windows faces east, you will only have light coming in from that direction in the morning. If you have room to put a sewing cabinet under the bank of windows, then you should place your machine there for taking advantage of the lighting. If you have enough room on the 13' wall that has the 2' window in the corner, than that wall should be your design wall. That way the afternoon light (from the south/west) will not be hitting your fabric on the design wall. The north wall with the door could get a bookcase or dresser. You didn't state if the west wall has a closet, but if so then you have storage for your future stash.
Congrats!