You can really wear anything you like which is part of the nice thing about being a stay at home mom. However, it may be tempting to wear slouch clothes all day. I would encourage you to wear things you would be comfortable going shopping in.
lots of stay at home moms around here wear jeans and tops, jeans and sweaters, jeans and sweatshirts, jeans and t shirts. basically jeans and everything else.
Find some jeans that fit well and look nice on you, but that are not "mom" jeans. Whatever you would normally wear to be comfortable but still confident will work.