Yup, the pinkish belly is usually a good indicator that the snake is in shed. Bump your humidity and as long as your husbandry has been good to this point you should be seeing a nice, one-piece shed anywhere from 3-8 or 9 days from now. My BP always goes through the entire shed process and sheds on the 4th day, but he's on the quick side of the spectrum. My other snakes are always at least 6 days.