dude, there's no way your mom noticed that shit... she saw you kickin the leaves or whatever... she just wants you to be honest... i mean seriously... do any kids actually think their parents notice these extremely minimal things???? hell no, they saw you and are trying to just get you to come clean.... your step dad doesn't care... so atleast you have 1/2 your parental figures on 'your side' just tell her now and get it over with...

honestly, i'm a father.. and my son isn't old enough for this yet (he's only 2) but even if i hated weed/drugs, i'd rather have him be honest with me, then lie to my face....