Congrats! It a good feeling to get your first successful smoke under your belt. I've had my #1 long enough now that I know I can smoke baby-backs at 225, open the door at 5 hours and they are perfect every time. I serve sauce on the side, so no saucing and putting back in the smoker for me. Just a 1+ hour rest double wrapped in foil. At 235, baby backs would almost certainly be over-cooked at 6 hours, so good thing you checked at 4.5 hours.