"waist" is kinda general. "belt line" and "hips" are a lot more specific. Top diaper tapes need to make it around your belt line, ideally leaving about 5-10" of space between the tapes. But even if the top tapes can make it to the tape panel, (for example, with a separation of maybe 12") then the lower tapes won't be able to make it. They have to go around your hips, which are wider than your belt, plus the front wing has to come out and up at a diagonal, which wastes some width. (and it takes even more material if your diaper is a bit too short lengthwise) Too many diaper manufacturers figure only the top tapes when indicating what size they "fit", and aren't practical at the lower end of the indicated range.
You probably can fit into most size Small adult diapers.