Took ages to come up with an answer to this because... honestly, it's kind of a difficult one for me to answer. n.n; Prior to transitioning and estradiol ramping up my sense of smell a thousandfold, between constant 'colds' that were undiagnosed hay fever and that sense just generally not being much to write home about (to say nothing of well, the actual details of my childhood itself) I don't... have a whole lot of scent memories from back in the day in general. One of those senses that always sat in the background until relatively more recently and all!
... All that said however, the smell of good food cooking on the stove, if not terribly nostalgic on its own, will always be a source of comfort for me. <3