it is a leatherworking recipe. ask friends or guildmembers if they can make the item for you if you provide the scales.
sounds like you dont skin though. so killing those turtles and not skinning them just killed your % chance of getting more turtle scales.
the turtles N of theramore and E of gadgetzan have higher chance of dropping/skinning turtle scales. these are high 30s, low 40s turtles, right around the right level to wear turtle scale gear.
the best drop rate ive seen are the turtles in hinterlands, but assuming you're around lvl 30 for SS, it'll be a while before you can fight the ones in hinterlands. by then you wont need the turtle scale gear.