May I ask why aspen? At the moment she's in a 15qt tub with coconut chunk bedding. I do have some aspen on hand but I was switching away from it because my other snake gets it in his mouth when eating.
Added security aspen allows them to burrow which is not the case of other bedding, make sure you downsize to a 6 quarts tub as well, 15 quarts is huge for such a tiny hatchling, good luck.